实验2 C++数组与指针

一．实验目的：

1. 掌握一维数组和二维数组的定义、赋值和输入输出的方法。
2. 掌握字符数组和字符串函数的使用。
3. 通过实验进一步掌握指针的概念，会定义和使用指针变量。
4. 能正确使用数组的指针和指向数组的指针变量。
5. 能正确使用字符串的指针和指向字符串的指针变量。
6. 能正确使用引用型变量。

二．实验内容：

1. 运行调试第5章编程示例5-3，5-4，5-5扑克发牌程序；完成练习题5.3.1，5.4.1, 5.5.1和7.5.2；
2. 运行调试第6章编程示例6-3数组排序器；完成以下练习：
   (1) 改进sort函数；
   (2) 用vector改造程序，使其支持变长数组；
   (3) 用char类型来改造程序具有更好输入方式，使其能一次性输入多个数组元素；
   (4) 用string类型来改造程序具有更好输入方式，使其能一次性输入多个数组元素；

三．示例代码：

　　1.第5章编程示例5-3扑克发牌程序:

#include <iostream>
#include <cstdlib>
#include <ctime>
#include <cmath>
using namespace std;

int rand_0toN1(int n);
void draw_a_card();

char *suits[4] = {"hearts", "diamonds", "spades", "clubs"};
char *ranks[13] = {"ace", "two", "three", "four", "five",
"six", "seven", "eight", "nine",
"ten", "jack", "queen", "king" };

int main() {
int n, i;

srand(time(NULL)); // Set seed for random numbers.

while (1) {
cout << "Enter no. of cards to draw (0 to exit): ";
cin >> n;
if (n == 0)
break;
for (i = 1; i <= n; i++)
draw_a_card();
}
return 0;
}

// Draw-a-card function
// Performs one card-draw by getting a random 0-4 and a random
// 0-12. These are then used to index the string arrays, ranks
// and suits.
//
void draw_a_card() {
int r; // Random index (0 thru 12) into ranks array
int s; // Random index (0 thru 3) into suits array

r = rand_0toN1(13);
s = rand_0toN1(4);
cout << ranks[r] << " of " << suits[s] << endl;
}

// Random 0-to-N1 Function.
// Generate a random integer from 0 to N-1.
//
int rand_0toN1(int n) {
return rand() % n;
}

　　2.第6章编程示例6-3数组排序器:

#include <iostream>
using namespace std;

void sort(int n);
void swap(int *p1, int *p2);

int a[10];

int main () {
int i;

for (i = 0; i < 10; i++) {
cout << "Enter array element #" << i << ": ";
cin >> a[i];
}
sort(10);

cout << "Here are all the array elements, sorted:" << endl;
for (i = 0; i < 10; i++)
cout << a[i] << " ";

cout << endl;
system("PAUSE");
return 0;
}

// Sort array function: sort array named a, having n elements.
// 
void sort (int n) {
int i, j, low;

for(i = 0; i < n - 1; i++) {

// This part of the loop finds the lowest
// element in the range i to n-1; the index
// is set to the variable named low.

low = i;
for (j = i + 1; j < n; j++)
if (a[j] < a[low])
low = j;

// This part of the loop performs a swap if
// needed.

if (i != low)
swap(&a[i], &a[low]);
}
}

// Swap function.
// Swap the values pointed to by p1 and p2.
//
void swap(int *p1, int *p2) {
int temp = *p1;
*p1 = *p2;
*p2 = temp;
}