C++ Primer Plus(第6版)编程练习答案——第4-8章

原创 已于 2025-11-21 08:29:17 修改 · 置顶 · 437 阅读 · 1 ·
CC 4.0 BY-SA版权
版权声明：本文为博主原创文章，遵循 CC 4.0 BY-SA 版权协议，转载请附上原文出处链接和本声明。
文章标签：

#c++ #开发语言 #算法 #学习

于 2024-12-10 10:36:02 首次发布

PS：自学C++ PrimerPlus (第6版)中，程序每章习题集中在一起，运行时每次注释 main 函数中的 test 即可。如有错误或者效率低的地方欢迎指出，有疑问也欢迎一起讨论。

目录

第4章练习题答案

#include<string>
#include<iostream>
#include<sstream>
#include<vector>
#include<iomanip>
#include<cstring>
#include<array>
using namespace std;

void test1() 
{
	struct MyInfo
	{
		string first_name;
		string last_name;
		char grade{'A'};
		int age=0;
	}LiMing;

	cout << "What is your first name? ";
	getline(cin, LiMing.first_name);
	cout << "What is your last name? ";
	getline(cin, LiMing.last_name);
	cout << "What letter grade do you deserve? ";
	cin >> LiMing.grade;
	cout << "What is your age? ";
	cin >> LiMing.age;

	cout << "Name: " << LiMing.last_name << ", " << LiMing.first_name <<  endl;
	cout << "Grade: " << char(LiMing.grade + 1) << endl;
	cout << "Age: " << LiMing.age << endl;
}

void test2()
{
	string name;
	string dessert;

	cout << "Enter your name: \n";
	getline(cin, name);
	cout << "Enter your favorite dessert: \n";
	getline(cin, dessert);

	cout << "I have some delicious " << dessert << " for you, " << name << ".\n";
}

void test3_4()
{
	//char first_name1[30];
	//char last_name1[30];
	string first_name2;
	string last_name2;
	cout << "Enter your first name: ";
	//cin.getline(first_name1,30);
	getline(cin, first_name2);
	cout << "Enter your last name: ";
	//cin.getline(last_name1,30);
	getline(cin, last_name2);
	//char name1[65] = {};
	//char connect[3] = { ',', ' ','\0' };
	string name2 = "";
	//strcpy_s(name1, sizeof(name1), last_name1);
	//strcat_s(name1, sizeof(name1), connect);
	//strcat_s(name1, sizeof(name1), first_name1);

	name2 = last_name2 + ", " + first_name2;

	cout << "Here's the information in a single string: " << name2 << endl;
}

void test5_6_9()
{
	struct CandyBar {
		string brand = "Mocha Munch";
		double weight = 2.3;
		unsigned int calorie = 350;
	}snack;

	cout << snack.brand << endl;
	cout << snack.weight << endl;
	cout << snack.calorie << endl;


	CandyBar candy[3];
	candy[0].brand = "a";
	candy[0].weight = 0.5;
	candy[0].calorie = 120;
	cout << candy[0].brand << ", " << candy[0].weight << ", " << candy[0].calorie << endl;
	candy[1].brand = "b";
	candy[1].weight = 0.8;
	candy[1].calorie = 200;
	cout << candy[1].brand << ", " << candy[1].weight << ", " << candy[1].calorie << endl;
	candy[2].brand = "c";
	candy[2].weight = 0.9;
	candy[2].calorie = 340;
	cout << candy[2].brand << ", " << candy[2].weight << ", " << candy[2].calorie << endl;

	cout << "----------------test9----------------" << endl;
	CandyBar* pt = new CandyBar[3];
	pt->brand = "a1";
	pt->weight = 0.5;
	pt->calorie = 120;
	cout << pt->brand << ", " << pt->weight << ", " << pt->calorie << endl;
	(pt+1)->brand = "b1";
	(pt + 1)->weight = 0.8;
	(pt + 1)->calorie = 200;
	cout << (pt + 1)->brand << ", " << (pt + 1)->weight << ", " << (pt + 1)->calorie << endl;
	(pt + 2)->brand = "c1";
	(pt + 2)->weight = 0.9;
	(pt + 2)->calorie = 340;
	cout << (pt + 2)->brand << ", " << (pt + 2)->weight << ", " << (pt + 2)->calorie << endl;

	delete[] pt;
}
void test7_8() 
{
	struct piza
	{
		string company = "a";
		double diameter = 1;
		double weight = 2.5;
	}piza1;

	cout << "Enter the company of piza1: ";
	cin >> piza1.company;
	cout << "Enter the diameter: ";
	cin >> piza1.diameter;
	cout << "Enter the weight: ";
	cin >> piza1.weight;
	cout << "You enter：" << piza1.company << ", " << piza1.diameter << ", " << piza1.weight << endl;


	cout << "-------------test8--------------" << endl;
	piza* p = new piza;
	cout << "Enter the diameter: ";
	cin >> p->diameter;
	cout << "Enter the company of piza1: ";
	cin >> p->company;
	cout << "Enter the weight: ";
	cin >> p->weight;
	cout << "You enter：" << p->diameter << ", " << p->company << ", " << p->weight << endl;
	delete p;
}

void test10() 
{
	array<int, 3> score;
	cout << "Enter the first score: ";
	cin >> score[0];
	cout << "Enter the second score: ";
	cin >> score[1];
	cout << "Enter the third score: ";
	cin >> score[2];

	cout << score.size() << "次的平均分为：" << (score[0] + score[1] + score[2]) / score.size() << endl;

}

int main()
{
	//test1();
	//test2();
	//test3_4()
	//test5_6_9();
	//test7_8();
	test10();
	return 0;
}

第5章练习题答案

#include<iostream>
#include<array>
#include<cmath>
#include<string>
#include<cstring>

using namespace std;

void test1()
{
	int a, b;
	cout << "Enter the first integer: ";
	cin >> a;
	cout << "Enter the second integer: ";
	cin >> b;
	int sum = 0;
	while (a <= b)
	{
		
		sum += a;
		a++;
		
	}
	cout << "The sum of two number is " << sum << ".\n";
}

void test2()
{
	array<long double, 101> factorials;

	factorials[1] = factorials[0] = 1L;
	for (int i = 2; i < 101; i++)
		factorials[i] = i * factorials[i - 1];
	std::cout << 100 << "! = " << factorials[100] << std::endl;
}

void test3()
{
	int temp = 0;
	int integer;
	do
	{
		cout << "Enter an integer: ";
		cin >> integer;
		temp += integer;
	} 	while (integer);
	cout <<"The sum of these numbers is "<< temp << endl;
}

void test4()
{
	int year;
	for (year = 1; (100 + 10 * year) > (100 * pow(1.05, year)); year++);
	cout << year << "年后，Cleo的投资价值大于Daphne." << endl;
	cout << "Daphne：" << (100 + 10 * year) << ".\n";
	cout << "Cleo: " << 100 * pow(1.05, year) << ".\n";
}

void test5()
{
	string month[12]{"January", "February", "March", "April", "May", "June",
		"July", "August", "September", "October", "November", "December"};
	int sales_volume[12];
	int sum = 0;
	for (int i=0;i<12;i++) 
	{
		cout << month[i] << ": ";
		cin >> sales_volume[i];
		sum += sales_volume[i];
	}
	cout << "total sale volume: " << sum << endl;

	

}

void test6()
{
	string month[12]{ "January", "February", "March", "April", "May", "June",
	"July", "August", "September", "October", "November", "December" };
	int sales_volume[3][12];
	int sum[3] = { 0 };
	for (int j = 0; j < 3; j++)
	{
		cout << "请输入第" << j << "年每个月的销量.\n";
		for (int i = 0; i < 12; i++)
		{
			cout << month[i] << ": ";
			cin >> sales_volume[j][i];
			sum[j] += sales_volume[j][i];
		}
		cout<<"第" <<j+1<< "的销量： " << sum[j] << endl;
	}
	
	cout << "3年总销量: " << sum[0]+sum[1]+sum[2] << endl;
}

void test7()
{
	struct car {
		string manufacturer;
		int production_year;
	};
	int num;
	cout << "How many cars do you want to catalog? ";
	cin >> num;
	cin.get();//去除回车符
	car* p = new car [num];
	for (int i = 0; i < num;i++) 
	{
		cout << "Car #" << i+1 << ": \n";
		cout << "Please enter the maker: ";
		getline(cin, (p + i)->manufacturer);
		cout << "Please enter the year made: ";
		cin >> (p + i)->production_year;
		cin.get();//去除回车符
	}

	cout << "Here is your collection：\n";
	for (int i = 0; i < num; i++)
	{
		cout << (p + i)->production_year << " " << (p + i)->manufacturer << endl;
	}
	delete [] p;
}

void test8()
{
	cout << "Enter words (to stop, type the word done):" << endl;
	char word[256];
	cin >> word;
	int count = 0;
	while (strcmp(word, "done"))
	{
		count += 1;
		cin >> word;
	}
	cout << "You entered a total of " << count << " words." << endl;
}

void test9()
{
	cout << "Enter words (to stop, type the word done):" << endl;
	string word;
	cin >> word;
	int count = 0;
	while (word != "done")
	{
		count += 1;
		cin >> word;
	}
	cout << "You entered a total of " << count << " words." << endl;
}

void test10()
{
	cout << "Enter number of rows: ";
	int rows;
	cin >> rows;
	for (int i = 0; i < rows; i++) 
	{
		for(int j = 0; j < rows; j++)
		{
			if( j >= rows - i - 1)
			cout << "*";
			else cout << ".";
		}
		cout << endl;
	}

}

int main()
{
	//test1();
	//test2();
	//test3();
	//test4();
	//test5();
	//test6();
	//test7();
	//test8();
	//test9();
	test10();
}

第6章练习题答案

#include <iostream>
#include <cctype>
#include <array>
#include <string>
#include <vector>
#include <fstream>

using namespace std;

void test1() {
	char ch;
	cout << "Enter the text, type @ to terminate.\n";
	while ((ch=cin.get( )) && ch != '@') {
		if (!isdigit(ch)) {
			if (isupper(ch))
				ch = tolower(ch);
			else if(islower(ch))
				ch = toupper(ch);
			cout << ch;
		}
	}
}

void test2() {
	const int Size = 10;
	array <double, Size> donation{0};

	int i = 0, num=0;
	double sum=0,temp;

	cout << "Enter the donation value, type char to terminate.\n";
	while (cin >> temp && i < Size) {
		donation[i] = temp;
		sum += donation[i];
		i++;
	}
	if (!cin) {
		cout << "检测到非数字输入!" << endl;
	}
	double average = sum / i;

	for (double x : donation) {
		if (x > average)
			num++;
	}

	cout << "You have input " << i << " numbers, and the average is " << average << ".\n";
	cout << num << " numbers exceed the average." << endl;
}

void test3() {
	char ch;
	string str;

	cout << "Please enter one of the following choice: \n";
	cout << "c) carnivore\t\t p) pianist\nt) tree\t\t\t g) game\n";
	bool flag = false;
	while (!flag && cin >> ch) {
		flag = true;
		switch (ch) {
		case 'C':
		case 'c': str = "carnivore";
			break;
		case 'P':
		case 'p': str = "pianist";
			break;
		case 'T':
		case 't': str = "tree";
			break;
		case 'G':
		case 'g': str = "game";
			break;
		default: cout << "Please enter a c, p, t, g: ";
			flag = false;
			break;
		}
	}
	cout << "A maple is a " << str << endl;
}

void test4() {
	const int strsize = 20;
	struct bop {
		char fullname[strsize];	//real name
		char title[strsize];	//job title
		char bopname[strsize];	//secret BOP name
		int preference;			//0=fullname, 1=title, 2=bopname
	};

	bop benevolents[5] = { 
		{"Wimp Macho","teacher","king",0},
		{"Raki Rhodes","Junior Programmer","solder",1},
		{"Celia Laiter","MIPS","MIPS",2},
		{"Hoppy Hipman","Analyst Trainee","fly",1},
		{"Pat hand","students","LOOPY",2},
	};

	cout << "Benevolent Order of Programmers Report: \n";
	cout << "a) display by name\t b) display by title\nc) display by bopname\t d) dispaly by preference\nq) quit\n";

	char ch;
	bool flag = true;
	cout << "Enter your choice: ";
	while (flag && cin>>ch) {
		switch (ch) {
		case 'a':
			for (bop x : benevolents) {
				cout << x.fullname << endl;
			} break;
		case 'b':
			for (bop x : benevolents) {
				cout << x.title << endl;
			} break;
		case 'c':
			for (bop x : benevolents) {
				cout << x.bopname << endl;
			} break;
		case 'd':
			for (bop x : benevolents) {
				switch (x.preference){
				case 0:cout << x.fullname << endl; break;
				case 1:cout << x.title << endl; break;
				case 2:cout << x.bopname << endl; break;
				}
			} break;
		case 'q':flag = false;
			cout << "Bye!" << endl;
			break;
		}
		if (flag) {
			cout << "Next choice: ";
		}
	}
}

void test5() {
	int income;
	double tax;

	cout << "Please enter you income: \n";
	while (cin >> income && income >= 0) {
		if (income <= 5000) {
			tax = 0;
		}
		else if (income >= 5001 && income <= 15000) {
			tax = 5000 * 0.0 + (income - 5000) * 0.1;
		}
		else if (income >= 15001 && income <= 35000) {
			tax = 5000 * 0.0 + 10000 * 0.1 + (income - 15000) * 0.15;
		}
		else if (income >= 35001) {
			tax = 5000 * 0.0 + 10000 * 0.1 + 20000 * 0.15 + (income - 35000) * 0.20;
		}
		cout << "Your personal income tax is " << tax << "tvarp." << endl;
		cout << "Enter you income:\n";
	}
}

void test6() {

	struct donors {
		string name;
		double funds;
	};

	cout << "Please enter the number of patrons: ";
	int num;
	cin >> num;

	donors* p = new donors[num];

	cout << "Please enter the name of patrons, and the funds.\n";
	int i = 0;
	while (i < num) {
		cout << "#" << i + 1 << ": ";
		cin >> (p + i)->name;
		cin >> (p + i)->funds;
		i++;
	}
	cout << "Below are some important patrons.\n";
	int j1 = 0;
	for (int i = 0; i < num; i++) {
		if ((p + i)->funds > 10000) {
			cout << (p + i)->name << "\t" << (p + i)->funds << endl;
			j1++;
		}
	}
	if (0 == j1) {
		cout << "none!\n";
	}

	int j2 = 0;
	cout << "other patrons:\n";
	for (int i = 0; i < num; i++) {
		if ((p + i)->funds <= 10000) {
			cout << (p + i)->name << "\t" << (p + i)->funds << endl;
			j2++;
		}
	}
	if (0 == j2) {
		cout << "none!\n";
	}
}

void test7() {
	cout << "Enter words (q to quit):\n";
	vector<string> words{};
	int i = 0;
	int num_vowel = 0, num_consonant = 0, num_else = 0;

	string word;
	while ((cin >> word) && word != "q") {
		words.push_back(word);
		if (!isalpha(words[i][0])) {
			num_else++;
		}
		else 
		{
			switch (words[i][0]) {
			case 'a':
			case 'A':
			case 'e':
			case 'E':
			case 'i':
			case 'I':
			case 'o':
			case 'O':
			case 'u':
			case 'U':num_vowel++; break;
			default:num_consonant++; break;
			}
		}
		i++;
	}

	cout << num_vowel << " words begining with vowels\n";
	cout << num_consonant << " words begining with consonants\n";
	cout << num_else << " others.\n";
}

void test8() {
	string filename;
	cout << "enter the filename you want to open: ";
	cin >> filename;
	ifstream inFile;
	inFile.open(filename);

	while (!inFile.is_open()) {
		cout << "Could not open the file " << filename << endl;
		cout << "Please cheack out the file.\n";
		cout << "-----------------------------\n";
		cout << "enter the filename again: ";
		cin >> filename;
		inFile.open(filename);
	}

	char ch;
	int charCount = 0;
	while (inFile.get(ch)) {
		++charCount;
		cout << ch;
	}
	inFile.close();

	cout << "总字符数：" << charCount << endl;
}

void test9() {
	struct donors {
		string name;
		double funds;
	};

	string filename;
	cout << "enter the filename you want to open: ";
	cin >> filename;
	ifstream inFile;
	inFile.open(filename);

	while (!inFile.is_open()) {
		cout << "Could not open the file " << filename << endl;
		cout << "Please cheack out the file.\n";
		cout << "-----------------------------\n";
		cout << "enter the filename again: ";
		cin >> filename;
		inFile.open(filename);
	}

	string line;
	//getline(inFile,line);第一种
	//int num;
	//num = stoi(line);

	int num;
	(inFile >> num).get();//第二种

	cout << "人数：" << num << endl;
	donors* p = new donors[num];

	int i = 0, j = 0;
	while (i < num) {
		getline(inFile, (p + i)->name);
		//getline(inFile, line);
		//(p + i)->funds = stod(line);	//第一种

		(inFile >> (p + i)->funds).get();//第二种
		i++;
	}
	inFile.close();

	cout << "Below are some important patrons:\n";
	int j1 = 0;
	for (int i = 0; i < num; i++) {
		if ((p + i)->funds > 10000) {
			cout << (p + i)->name << "\t" << (p + i)->funds << endl;
			j1++;
		}
	}
	if (0 == j1) {
		cout << "none!";
	}

	int j2 = 0;
	cout << "other patrons:\n";
	for (int i = 0; i < num; i++) {
		if ((p + i)->funds <= 10000) {
			cout << (p + i)->name << "\t" << (p + i)->funds << endl;
			j2++;
		}
	}
	if (0 == j2) {
		cout << "none!";
	}
	
}

int main() {
	//test1();
	//test2();
	//test3();
	//test4();
	//test5();
	//test6();
	//test7();
	//test8();
	test9();
}

第7章练习题答案

#include <iostream>
#include <array>
#include <cstring>

using namespace std;

double harmonic_mean(double x, double y) {
	return 2.0 * x * y / (x + y);
}

void test1() {
	double a, b;
	cout << "Please enter two number(enter 0 to quit): ";
	while (cin >> a && 0 != a && cin>> b && 0 != b) {
		cout << "The harmonic mean of " << a << " and " << b << " is " << harmonic_mean(a, b) << endl;
		cout << "\nPlease enter two number(enter 0 to quit): ";
	}
}

//------------------------------------------------------test2
const int max_size = 10;

int input_array(double a[], int b) {
	cout << "You can enter up to 10 scores(enter q to quit): ";
	int count = 0;
	while (count< max_size && cin >> a[count]) {
		count++;
		if (10 == count)
			break;
		cout << "Next score: ";
	}

	return count;
}
void show_score(double a[], int b) {
	cout << "You enter socre: ";
	for (int i = 0; i < b; i++) {
		cout << a[i] << "  ";
	}
}
void caculate_score(double a[], int b) {
	double sum = 0;
	for (int i = 0; i < b; i++) 
		sum += a[i];
	double mean = sum / b;

	cout << "\nThe average of these score is " << mean << ".\n";
}
void test2() {
	double score[max_size];
	int real_size = input_array(score, max_size);

	show_score(score, real_size);
	caculate_score(score, real_size);
}


//---------------------------------------------test3

struct box {
	char maker[40];
	float height;
	float width;
	float length;
	float volume;
};

void show_box(box a) {
	cout << "maker: " << a.maker << endl;
	cout << "height: " << a.height << endl;
	cout << "width: " << a.width << endl;
	cout << "length: " << a.length << endl;
	cout << "volume: " << a.volume << endl;
}

void calculate_box(box *p) {
	p->volume = p->length * p->height * p->width;
}
void test3() {
	box a{ "rectangle",3.0, 2.0, 1.2, 0 };
	show_box(a);
	calculate_box(&a);
	cout << "The volume of the box is " << a.volume << endl;
}

//---------------------------------------------------test4
long double probability(unsigned numbers, unsigned picks)
{
	long double result = 1.0;  
	long double n;
	unsigned p;

	for (n = numbers, p = picks; p > 0; n--, p--)
		result = result * n / p;
	return result;
}

void test4() {
	long double re = probability(47, 5) * probability(27, 1);
	cout << "The probability of you winning the jackpot is " << 1/re;
}

//---------------------------------------------------test5
unsigned long long fun1(int i) {

	unsigned long long re = 0;
	if (0 == i ) {
		re = 1;
	}
	else if (i>0) {
		re = i * fun1(i - 1);
	}
	return re;
}

void test5() {
	cout << "Please enter a positive integer (negative to quit):\n";
	int integer;
	while (cin>>integer) {
		if (integer < 0) {
			break;
		}
		unsigned long long re = fun1(integer);
		cout << integer << "! = " << re << endl;
		cout << "Enter another positive integer (negative to qiut): \n";
	}
	cout << "exit...\n";
}

//---------------------------------------------------test6
int Fill_array(double* p, int size) {
	cout << "Enter a double value: ";
	double temp;
	int i = 0;
	while (i < size && cin >> temp) {
		*(p+i) = temp;
		i++;
	}
	return i;
}

void Show_array(double* p, int size) {
	for (int i = 0; i < size; i++) {
		cout << *(p + i)<<" ";
	}
	cout << endl;
}

void Reverse_array(double* p, int size) {
	double temp;
	for (int i = 0; i < size - i; i++) {
		temp = *(p + i);
		*(p + i) = *(p + size - i - 1);
		*(p + size - i - 1) = temp;
	}
}
void test6() {
	const int max_size = 5;
	double array[max_size];
	int size = Fill_array(array, max_size);
	cout << "You enter: ";
	Show_array(array, size);
	
	Reverse_array(array, size);
	cout << "reverse array: ";
	Show_array(array, size);

	Reverse_array(array+1, size-2);
	cout << "reverse part of  array: ";
	Show_array(array, size);
}

//---------------------------------------------------test7
double * fill_array(double *p, double *j)
{
	double temp;
	int i;
	for (i = 0; p+i < j; i++)
	{
		cout << "Enter value #" << (i + 1) << ": ";
		cin >> temp;
		if (!cin)    // bad input
		{
			cin.clear();
			while (cin.get() != '\n')
				continue;
			cout << "Bad input; input process terminated.\n";
			break;
		}
		else if (temp < 0)     // signal to terminate
			break;
		*(p+i) = temp;
	}
	return p+i;
}

void show_array(double* p, double* j)
{
	for (int i = 0; p + i < j; i++)
	{
		cout << "Property #" << (i + 1) << ": $";
		cout << *(p+i) << endl;
	}
}

void revalue(double r, double* p, double* j)
{
	for (int i = 0; p+i < j; i++)
		*(p+i) *= r;
}

void test7() {
	const int Max = 5;
	double properties[Max];

	double * size = fill_array(properties, properties + Max);
	show_array(properties, size);
	if ((size-properties) > 0)
	{
		cout << "Enter revaluation factor: ";
		double factor;
		while (!(cin >> factor))    // bad input
		{
			cin.clear();
			while (cin.get() != '\n')
				continue;
			cout << "Bad input; Please enter a number: ";
		}
		revalue(factor, properties, size);
		show_array(properties, size);
	}
	cout << "Done.\n";
}

//---------------------------------------------------test8-a
const int Seasons = 4;
const char* Snames[Seasons] =
{ "Spring", "Summer", "Fall", "Winter" };

void fill(double *pa)
{
	for (int i = 0; i < Seasons; i++)
	{
		std::cout << "Enter " << *(Snames+i) << " expenses: ";
		std::cin >> *(pa+i);
	}
}

void show(double * da)
{
	double total = 0.0;
	std::cout << "\nEXPENSES\n";
	for (int i = 0; i < Seasons; i++)
	{
		std::cout << Snames[i] << ": $" << *(da+i) << '\n';
		total += *(da + i);
	}
	std::cout << "Total: $" << total << '\n';
}

void test8_a() {
	
	double expenses[4];
	fill(expenses);
	show(expenses);
}
//---------------------------------------------------test8-b
struct cost {
	double expenses[4];
}cost_all;

void fill_b(cost* pa)
{
	for (int i = 0; i < Seasons; i++)
	{
		std::cout << "Enter " << *(Snames + i) << " expenses: ";
		std::cin >> (pa->expenses)[i];
	}
}

void show_b(cost* da)
{
	double total = 0.0;
	std::cout << "\nEXPENSES\n";
	for (int i = 0; i < Seasons; i++)
	{
		std::cout << Snames[i] << ": $" << (da->expenses)[i] << '\n';
		total += (da->expenses)[i];
	}
	std::cout << "Total: $" << total << '\n';
}

void test8_b() {
	fill_b(&cost_all);
	show_b(&cost_all);
}

//---------------------------------------------------test9
const int SLEN = 30;
struct student {
	char fullname[SLEN];
	char hobby[SLEN];
	int ooplevel;
};

int getinfo(student pa[], int n) {
	char temp[SLEN];
	int level = 0;
	int i = 0;
	for (i = 0; i < n; i++) {
		cout << "#" << i + 1 << endl;
		cout << "Enter the name: ";
		cin.getline(temp, SLEN);
		if ('\0' == temp[0])
			break;
		strcpy_s((pa + i)->fullname, temp);

		cout << "Enter the hobby: ";
		cin.getline(temp, SLEN);
		strcpy_s((pa + i)->hobby, temp);

		cout << "Enter the ooplevel: ";
		while (!(cin >> level)) { // 确保输入的是整数
			cout << "Invalid input. Please enter an integer: ";
			cin.clear(); // 清除错误标志
			cin.ignore(numeric_limits<streamsize>::max(), '\n'); // 忽略无效输入
		}
		(pa + i)->ooplevel = level;
		cin.get();
	}
	return i;
}

void display1(student st) {
	cout << "fullname: " << st.fullname << endl;
	cout << "hobby: " << st.hobby << endl;
	cout << "ooplevel: " << st.ooplevel << endl;
}

void display2(const student *ps) {
	cout << "fullname: " << ps->fullname << endl;
	cout << "hobby: " << ps->hobby << endl;
	cout << "ooplevel: " << ps->ooplevel << endl;
}

void display3(const student pa[],int n) {
	for (int i = 0; i < n; i++) {
		cout << "fullname: " << pa->fullname << endl;
		cout << "hobby: " << pa->hobby << endl;
		cout << "ooplevel: " << pa->ooplevel << endl;
	}
}

void test9() {
	cout << "Enter class size: ";
	int class_size;
	cin >> class_size;
	while (cin.get() != '\n')
		continue;
	student* pre_stu = new student[class_size];
	int entered = getinfo(pre_stu, class_size);
	for (int i = 0; i < entered; i++) {
		display1(pre_stu[i]);
		display2(&pre_stu[i]);
	}
	display3(pre_stu, entered);
	delete[]pre_stu;
	cout << "Done\n";
}

//---------------------------------------------------test10
double calculate(double a, double b, double (*fun)(double, double)) {
	return fun(a, b);
}

double add(double x,double y) {
	double re = x + y;
	cout << x << " + " << y << " = " << re << endl;
	return re;
}

double multiply(double x, double y) {
	double re = x * y;
	cout << x << " * " << y << " = " << re << endl;
	return re;
}

double subtract(double x, double y) {
	double re = x - y;
	cout << x << " - " << y << " = " << re << endl;
	return re;
}

double(*pf[3])(double, double) = {add,multiply,subtract};

void test10() {
	double a, b;
	cout << "enter two double value: ";
	cin >> a >> b;
	for (int i = 0; i < 3; i++) {
		double q = calculate(a, b, (*pf[i]));
	}
}

int main() {
	//test1();
	//test2();
	//test3();
	//test4();
	//test5();
	//test6();
	//test7();
	//test8_a();
	//test8_b();
	//test9();
	test10();
}

第8章练习题答案

#include <iostream>
#include <string>
#include <cctype>
#include <cstring>
using namespace std;

// -------------------------------------------------test1
int count1 = 0;
void show(const char* str, int n = 0) {
	count1++;
	if (0 == n)
		cout << str << endl;
	else {
		for (int i = 0; i < count1; i++) 
			cout << str << " ";
		cout << endl;
	}
		
}
void test1() {
	const int size = 100;
	cout << "Enter a string: ";
	char str[size];
	cin.getline(str, size);
	for (int i = 0; i < 3; i++) {
		show(str);
		show(str, 2);
	}
}

// -------------------------------------------------test2
struct CandyBar {
	string brand;
	float weight;
	int calories;
};
void set_candybar(CandyBar& candy, const char* str = "Millennium Munch",
	double candy_weight = 2.85, int candy_calories = 350) {
	candy.brand = str;
	candy.weight = candy_weight;
	candy.calories = candy_calories;
}
void show_candybar(const CandyBar& candy) {
	cout << "---\n";
	cout << "brand: " << candy.brand << endl;
	cout << "weight: " << candy.weight << endl;
	cout << "calories: " << candy.calories << endl;
}
void test2() {
	CandyBar my_candy;
	char brand[50];
	float weight;
	int calories;
	cout << "Enter the brand of your candy: " ;
	cin.getline(brand,50);
	cout << "Enter the weight of your candy: " ;
	cin >> weight;
	cout << "Enter the calories of your candy: " ;
	cin >> calories;
	set_candybar(my_candy, brand);
	show_candybar(my_candy);
	set_candybar(my_candy, brand, weight);
	show_candybar(my_candy);
	set_candybar(my_candy, brand, weight, calories);
	show_candybar(my_candy);
}
// -------------------------------------------------test3
void to_upper(string& str) {
	for (char &x : str)
		x = toupper(x);
	cout << str << endl;
}

void test3() {
	cout << "Enter a string (q to quit): ";
	string str;
	getline(cin, str);
	while ("q" != str && "Q" != str) {
		to_upper(str);
		cout << "Next string （q to quit）:";
		getline(cin, str);
	}
	cout << "Bye." << endl;
}
// -------------------------------------------------test4
struct stringy {
	char* str;
	int ct;		//length of string(not counting "\0")
};
void set(stringy& stry, char* str_temp) {
	stry.ct = strlen(str_temp);
	stry.str = new char[stry.ct + 1];
	strcpy_s(stry.str, stry.ct+1, str_temp);
}
void show4(const stringy &stry, int ct = 1) {
	while (ct) {
		cout << stry.str << endl;
		ct--;
	}
}
void show4(const char* str, int num = 1) {
	while (num) {
		cout << str << endl;
		num--;
	}
}
void test4() {
	stringy beany;
	char testing[] = "Reality isn't what is used to be.";
	set(beany, testing);

	show4(beany);
	show4(beany, 2);
	testing[0] = 'D';
	testing[1] = 'u';
	show4(testing);

	show4(testing, 3);
	show4("Done!");
}
// -------------------------------------------------test5
template <typename T>
T max5(T * array) {
	T temp = array[0];
	for (int i = 0; i < 5;i++) {
		if (array[i] > temp) {
			temp = array[i];
		}
	}
	return temp;
}
void test5() {
	int int_array[5] = { 1,2,3,4,5 };
	double double_array[5] = { 1.2, 2.2, 33.2, 4.2 ,5.2 };
	cout << "Max int: " << max5(int_array) << endl;
	cout << "Max double: " << max5(double_array) << endl;
}
// -------------------------------------------------test6
template <typename T>
T maxn(T* array, int num) {
	T temp = array[0];
	for (int i = 0; i < num; i++) {
		if (array[i] > temp) {
			temp = array[i];
		}
	}
	return temp;
}
template<> const char* maxn(const char* str[], int num) {
	int max_length= strlen(str[0]);
	int max_id = 0;
	for (int i = 0; i < num;i++) {
		if (strlen(str[i]) > max_length) {
			max_length = strlen(str[i]);
			max_id = i;
		}
	}
	return str[max_id];
}
void test6() {
	int int_array[6] = { 1,2,3,4,5,100 };
	double double_array[4] = { 1.2, 2.2, 33.2, 4.2 };
	cout << "Max int: " << maxn(int_array,6) << endl;
	cout << "Max double: " << maxn(double_array,4) << endl;
	const char* str[5] = { "apple","banana","orange_123","potato","watermelon" };
	cout << "最长字符串：" << maxn(str, 5) << endl;
	cout << "最长字符串地址：" << (void*)maxn(str, 5) << endl;
}
// -------------------------------------------------test7
template <typename T>
T SumArray(T arr[], int n)
{
	T sum = T();
	cout << "template A\n";
	for (int i = 0; i < n; i++)
		sum += arr[i];
	return sum;
}

template <typename T>
T SumArray(T* arr[], int n)
{
	cout << "template B\n";
	decltype (*arr[0] + *arr[1]) sum= 0;
	if (n > 0){
		for (int i = 0; i < n; i++)
			sum += *arr[i];
	}
	
	return sum;
}
struct debts
{
	char name[50];
	double amount;
};
void test7() {
	int things[6] = { 13, 31, 103, 301, 310, 130 };
	struct debts mr_E[3] =
	{
		{"Ima Wolfe", 2400.0},
		{"Ura Foxe", 1300.0},
		{"Iby Stout", 1800.0}
	};
	double* pd[3];
	for (int i = 0; i < 3; i++)
		pd[i] = &mr_E[i].amount;
	cout << "Listing Mr. E's counts of things:\n";
	cout << "Total of tings:" << SumArray(things, 6) << endl;
	cout << "Listing Mr. E's debts:" << SumArray(pd, 3) << endl;
}


void main() {
	//test1();
	//test2();
	//test3();
	//test4();
	//test5();
	//test6();
	test7();
}
life_007
关注
C++primer plus习题+答案
yj
05-16 1895
这两条语句并不真正等价，虽然对于某些系统来说，它们是等效的。最重要的是，只有在使用ASCII码的系统上，第一条语句才将grade设置为字符A，而第二条语句还可以用于使用其他编码的系统。因为最大的long值为20亿，即有10位数。longlong类型可提供19位有效数字，超过了double保证的13位有效数字。有多种整型类型，可以根据特定需求选择最适合的类型。例如，可以使用short来存储空格，使用long来确保存储容量，也可以寻找可提高特定计算的速度的类型。33L的类型为long，常量33的类型为int。
C++ Primer Plus 第6版 第6章 编程练习答案
Anna_L的博客
07-30 759
1
C++PrimerPlus(第六版)编程练习答案
05-24
C++Primer Plus(第六版)编程练习答案，解答的比较详细
c++-primer-plus(第六版)-编程练习答案
04-18
c++-primer-plus(第六版)中文版 （人民邮电出版社）-课后编程练习答案
C++ primer plus课后编程练习题答案
04-22
C++ primer plus 答案，QT亲自运行成功，含有课后练习题，编程练习题。
C++ Primer Plus 第六版 所有章节课后编程练习答案
xiaojimmychen的专栏
11-01 9万+
C++ Primer Plus 第六版 所有章节课后编程练习答案
C++ Primer Plus第六章编程练习答案
A_B_CDEFGH的博客
04-14 506
总结： 总结： 总结： 总结： 总结： 若是结构中使用string对象存储字符串，则使用函数而不是类方法。 因为早期的C++包含了istream类，只考虑到了基本类型。string类是后面才出现的。 9 总结： 8 总结：
C++ Primer Plus(第6版)课后编程习题答案（自敲）——第六章
weixin_56493138的博客
01-27 1936
C++ Primer Plus（第6版）课后编程习题答案（自敲）——第六章
C++ Primer Plus（第六版）编程练习答案 所有章节汇总
清水河C罗——Leonardo-Liu
01-14 4万+
本博客汇总了本人历时一年学完《C++ Primer Plus （第6版）》所做的所有编程练习的答案，供大家学习参考和交流。 以下附上各章节的答案详解博客地址，以及源码工程下载地址。 PS：源码下载大部分都是需要积分的，当时设置的时候好像有点乱，有的是1积分，有的是3积分，最难的第12章和第13章我设置的是不要积分，大家都可以下载下来自己运行一下看看结果。 第 2 章 开始学习C++： ...
C++ Primer Plus (第6版）中文版 第四章编程练习答案（个人作答）
weixin_55720656的博客
11-29 921
4.13编程练习 编写一个C++程序，如下述输出示例所示的那样请求并显示信息： What is your first name? Betty Sue What is your lastname? Yewe What letter grade do you deserve? B What is your age? 22s Name: Yewe, Betty Sue Grade: C Age: 22 注意，该程序应该接受的名字包含多个单词。另外，程序将向下调整成绩，即向上调一个字母。假设用户请求A、B或C,
C++ Primer Plus 第六版 第6版 中文版 编程练习答案
08-17
C++ Primer Plus 第六版 第6版 中文版 编程练习答案 全面详细，助力深入理解C++精髓
c++ primer plus 第六版 课后习题答案
01-15
c++ primer plus 第六版 课后习题答案
c++primerplus(第六版)课后编程练习答案.pdf
05-20
c++primerplus(第六版)课后编程练习答案.pdf
C primer plus 编程题答案
08-29
1．编写一个程序，创建一个具有26个元素的数组，并在其中存储26个小写字母。并让该程序显示该数组的内容。#include<stdio.h> int main(void) { char ABC[26]; int i; for(i=0;i<26;i++) ABC[i] = 'a' + i; for(i=0;i<26;i++) printf("%c",ABC[i]); printf("\n"); return(0); }
C++ primer plus 课后习题答案
03-30
这个文件是我买的资料。我看过，和C++ primer plus 这本书的课后习题非常吻合。
C Primer Plus第六版(中文版)编程练习答案(完美修订版)汇总
热门推荐
CLOVER的博客
01-11 15万+
本文是博主编写的C Primer Plus第六版(中文版)编程练习答案的所有链接
C++ primer Plus（第六版）中文版 第六章 分支语句和逻辑运算符 编程练习答案
AirHead
12-30 952
第六章 分支语句和逻辑运算符1. 编写一个程序，读取键盘输入，直到遇到@符号为止，并回显输入（数字除外），     同时将大写字符转换为小写，将小写字符转换为大写（别忘了cctype函数系列）。 1.1 使用 if-else-if #include &lt;iostream&gt; int main() {     using namespace std;     char a;      ...
C++primer plus编程练习参考答案
margaret522的博客
06-13 2万+
第2章 开始学习C++ -1编写一个C++程序,:它显示您的姓名和地址。 2.编写学个C+程序,它要求用广输入一个以long-为单位的距离,然后将它转换为码(一-long 等手:220码)。3.编写一个C行程序,它使用3个用户定义的函数~(包括maini()>,并生成下面的输出” Three-biind ,micer rhree blind:miceseerhow they . run ..seehow. they run 其p:个函数要调用两次，.该函数生成前两行,另=个函数也被调用两次，并生成其
C Primer Plus 第6版 编程练习参考答案 第4章
weixin_58979213的博客
10-16 392
目前在学C Primer Plus，记录以下自己的学习过程 ^-^
评论
添加红包

请填写红包祝福语或标题

个

红包个数最小为10个

元

红包金额最低5元

当前余额3.43元 前往充值 >
需支付：10.00元
成就一亿技术人!
领取后你会自动成为博主和红包主的粉丝 规则
hope_wisdom
发出的红包
实付元
使用余额支付
点击重新获取
扫码支付
钱包余额 0

抵扣说明：

1.余额是钱包充值的虚拟货币，按照1:1的比例进行支付金额的抵扣。
2.余额无法直接购买下载，可以购买VIP、付费专栏及课程。

余额充值