C程序

1 写一个函数可以判断一个数是不是素数

#include<stdio.h>

#include <math.h>

int judge_prime(int i)

{

int j = 0;

for (j = 2; j <= sqrt(i); j++)

{

if(i%j==0)

{

return 0;

}

}

return 1;

}

int main()

{

int num ;

scanf("%d", &num);

int result=judge_prime(num);

while (result)

{

printf("%d\n", num);

break;

}

system("pause");

return 0;

}

2  写一个函数可以判断一年是不是闰年

#include<stdio.h>

int judge_leap(int year)

{

if (((year % 4 == 0) && (year % 100 != 0)) || (year % 400 == 0))

{

return 1;

}

return 0;

}

int main()

{

int y;

scanf("%d", &y);

int r = judge_leap(y);

while (r)

{

printf("this year is a leap year\n");

break;

}

system("pause");

return 0;

}

3 写一个函数，实现一个整形有序数组的二分查找

#include<stdio.h>

int binary_search(int arr[], int key, int left, int right)

{

int mid = 0;

while (left <= right)

{

mid = left - (left - right) / 2;

if (arr[mid] > key)

{

right = mid - 1;

}

else if (arr[mid] < key)

{

left = mid + 1;

}

else

{

return mid;

}

}

if (left>right)

{

return -1;

}

}

int main()

{

int arr[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9,10 };

int key = 6;

int ret = binary_search(arr, key, 4, 8);

if (ret != -1)

{

printf("%d\n",ret);

}

else

{

printf("不存在\n");

}

system("pause");

return 0;

}

4 写一个函数，调用一次就可以将参数的值增加1

#include<stdio.h>

void inc(int *p)

{

(*p)++;

}

int main()

{

int num = 2;

inc(&num);

printf("%d\n", num);

system("pause");

return 0;

}

5 在屏幕上输出以下图案：

#include<stdio.h>

void main()

{

int i = 0;

int j = 0;

for (i = 1; i <= 7; i++)

{

for (j = 1; j <= 7 - i; j++)

{

  printf(" ");

}

for (j = 1; j <= 2 * i - 1; j++)

{

printf("*");

}

printf("\n");

}

for (i = 6; i >= 1; i--)

{

for (j = 7-i; j > 0; j--)

{

printf(" ");

}

for (j = 2 * i - 1; j >= 1; j--)

{

printf("*");

}

printf("\n");

}

system("pause");

}

6 求1-1000的水仙花数

#include<stdio.h>

int main()

{

int i = 0;

int a = 0;

int b = 0;

int c = 0;

for (i = 100; i < 1000; i++)

{

a = i % 10;

b = i / 10 % 10;

c = i / 100;

if (i == a*a*a + b*b*b + c*c*c)

{

printf("%d ", i);

}

}

printf("\n");

system("pause");

return 0;

}

7 求Sn=a+aa+aaa+aaaa+aaaaa的前五项和，其中a是一个数字  例如：a=2

#include <stdio.h>

int main()

{

int a = 2;

int b = 0;

int sum = 0;

int j = 0;

for (j = 0; j < 5; j++)

{

b = b * 10 + 2;

sum = sum + b;

}

printf("%d\n", sum);

system("pause");

return 0;

}

8  编写一个程序，它从标准输入读取C源代码，并验证所有的花括号都正确的成对出现。

#include<stdio.h>  

int main()

{

int i = 0;

char ch;

while (1)

{

ch = getchar();

if ((ch == '}') && (i == 0))

{

break;

}

else if (ch == '{')

{

i++;

}

else if ((ch == '}') && (i != 0))

{

i--;

}

if (ch == '\n')

{

break;

}

}

if ((i == 0) && (ch != '}'))  //这里加上判断 ch != '}',因为可能前面输入的是成对，但又直接输入了‘}’  

{

printf("括号正确成对出现\n");

}

else

{

printf("括号非正确成对出现\n");

}

system("pause");

return 0;

}