小甲鱼C++快速入门——第三天

10视频—指针和数组

#include <iostream.h>
 
int main()
{
    int array[5]={1,2,3,4,5};
    int* ptr=array;
 
    cout << *ptr+2 << endl;//输出3。*ptr = 1
    cout << *(ptr+1) << endl;//输出为2
    return 0;
}

重载

#include <iostream.h>

void print(int *pBegin, int *pEnd)
{
	while(pBegin != pEnd)
	{
		cout << *pBegin;
		pBegin++;
	}
}
void print(char *pBegin, char *pEnd)
{
	while(pBegin != pEnd)
	{
		cout << *pBegin;
		pBegin++;
	}
}

int main()
{
	int num[5] = {1,2,3,4,5};
	char ch[5] = {'h', '1', '2', '3', '4'};

	print(num, num + 5);
	cout << endl;
	print(ch, ch + 5);
	cout << endl;

	return 0;
}

模板template

#include <iostream.h>

template <typename T>//模板template
void print(T *pBegin, T *pEnd)
{
	while(pBegin != pEnd)
	{
		cout << *pBegin;
		pBegin++;
	}
}

int main()
{
	int num[5] = {1,2,3,4,5};
	char ch[5] = {'h', '1', '2', '3', '4'};

	print(num, num + 5);
	cout << endl;
	print(ch, ch + 5);
	cout << endl;

	return 0;
}

11视频—结构

#include <iostream>
using namespace std;
#include <string>
#include <fstream>//文件操作
#include <Windows.h>//Sleep()


//定义结构体
struct fishOil
{
	string name;
	string ID;
	char sex;
};

//函数声明
bool writeDate(fishOil *pDate);
bool fishInit();
bool print();
bool record();

int main()
{
	//初始化
	fishInit();
	//实现数据的读取，记录
	while (true)
	{
		cout << "请选择进行的操作：" << endl;
		cout << "1.打印数据到屏幕 \n";
		cout << "2.录入数据 \n";
		cout << "3.退出程序 \n";

		char ch;
		cin >> ch;
		switch (ch)
		{
		case '1':
			print();
			break;
		case '2':
			record();
			break;
		case '3':
			return 0;
		default:
			break;
		}

	}

	system("pause");
	return 0;
}

//录入数据
bool record()
{
	fishOil tempOil;
	cout << "请输入姓名:";
	cin >> tempOil.name;
	cout << "请输入ID:";
	cin >> tempOil.ID;
	cout << "请输入性别:";
	cin >> tempOil.sex;
	//将数据写入到文件中
	if (writeDate(&tempOil))
	{
		return true;
	}
	else
	{
		return false;
	}
}


//输出文件中的数据
bool print()
{
	string temp;//临时变量
	//打开文件
	ifstream inFile("test.doc");
	if (inFile.is_open())
	{
		cout << "\n 正在输出数据……";
		//模拟进度条
		for (int i = 0; i < 100; i++)
		{
			cout.width(3);//字段宽度设置为3
			cout << i << '%';
			Sleep(50);
			cout << "\b\b\b\b";
		}

		cout << "\n\n";
		cout << "  姓名" << "  身份证" << "  性别" << endl;
		while (getline(inFile, temp))
		{
			cout << temp << endl;
		}
		cout << "\n\n";
		return true;
	}
	else
	{
		cerr << "文件读取错误" << endl;
		return false;
	}
}


bool writeDate(fishOil *pDate)
{
	ofstream outFile("test.doc", ios::app);//以追加的形式写入文件
	//检查文件打开正确否
	if (outFile.is_open())
	{
		outFile << pDate->name << " ";
		outFile << pDate->ID << " ";
		outFile << pDate->sex << '\n';

		outFile.close();//关闭文件
		cout << "数据已经保存到test.doc" << endl;
		return true;
	}
	else
	{
		cerr << "文件已被占用，打开错误" << endl;
		return false;
	}
}
bool fishInit()
{
	//初始化
	fishOil OilInit = { "小甲鱼", "fish_001", 'M'};
	//将初始化的内容写入到文件中
	if( writeDate(&OilInit) )
	{
		cerr << "初始化成功^_^" << endl;
		return true;
	}
	else
	{
		cerr << "初始化失败@_@" << endl;
		return false;
	}
}

视频12—传值、传址和传引用

值传递

#include <iostream.h>

void change(int age1, int age2);

int main()
{
	int age = 24;

	change(age, age + 1);//值传递，不是址传递,输出为25
	cout << "age = " << age << endl;//输出为24

	return 0;
}

void change(int age1, int age2)//值传递，不是址传递
{
	age1 = age2;
	cout << "age1 = " << age1 << endl;
}

址传递

#include <iostream.h>

void change(int *age1, int age2);

int main()
{
	int age = 24;

	change(&age, age + 1);//址传递,输出为25
	cout << "age = " << age << endl;//输出为25

	return 0;
}

void change(int *age1, int age2)//址传递
{
	*age1 = age2;
	cout << "age1 = " << *age1 << endl;
}

//交换两个变量【址传递】
#include<iostream.h>
void swap(int *n1, int *n2);

int main()
{
	int a,b;
	a = 1;
	b = 2;
	cout << "a = " << a
		<< ", b = " << b << endl;

	//交换两个变量的值
	swap(&a, &b);
	cout << "交换后的值为：" << "a = " << a
		<< ", b = " << b << endl;

	return 0;
}

void swap(int *n1, int *n2)
{
	int temp;
	temp = *n1;
	*n1 = *n2;
	*n2 = temp;
}

传引用

//引用传递
#include<iostream.h>
void swap(int &n1, int &n2);

int main()
{
	int a,b;
	a = 1;
	b = 2;
	cout << "a = " << a
		<< ", b = " << b << endl;

	//交换两个变量的值
	swap(a, b);
	cout << "交换后的值为：" << "a = " << a
		<< ", b = " << b << endl;

	return 0;
}

void swap(int &n1, int &n2)
{
	int temp;
	temp = n1;
	n1 = n2;
	n2 = temp;
}

视频13—联合、枚举和类型别名

联合

#include <iostream.h>

union T
{
	char *name;
	int a;
	char ch;
};

int main()
{
	T birthday;
	birthday.name = "WaHaHa";
	cout << "birthday.name = " << birthday.name << endl;

	birthday.a = 3;//此时birthday.name中的内容被覆盖
	cout << "birthday.a = " << birthday.a << endl;

	return 0;
}

枚举

//枚举
#include <iostream.h>

int main()
{
	//枚举中的值不是字符串，所以不用引号
	enum weekends{ Monday, Tuesday, Wednesday, Thursday, Friday};

	weekends today;
	today = Monday;
	cout << "today = " << today << endl;//输出0
	today = Wednesday;
	cout << "today = " << today << endl;//输出2

	return 0;
}

类型别名typedef

//类型别名typedef
#include <iostream.h>
typedef int* p;

int main()
{
	p point;
	int a = 123;
	point = &a;
	cout << "a = " << *point << endl;

	return 0;
}