C语言名企面试题2

1.打印
*
*
*

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*****
 ***
  *

#define _CRT_SECURE_NO_WARNINGS 1 

#include<stdio.h>
int main()
{
    int i = 0;
    int j = 0;
    int n = 0;
    for (n = 0; n <= 6; n++)
    {
        for (i = 0; i <= 6 - n; i++)
        {
            printf(" ");
        }
        for (j = 1; j <= 2*n+1; j++)
        {
            printf("*");
        }
        printf("\n");
    }
    for (n = 0; n <= 5; n++)
    {
        for (i = 0; i <= n+1; i++)    
        {
            printf(" ");
        }
        for (j = 1; j <= 11 - 2 * n ; j++)
        {
            printf("*");
        }
        printf("\n");
    }
    return 0;
}

2.求出0~999之间所有水仙花数并输出

#define _CRT_SECURE_NO_WARNINGS 1 

#include<stdio.h>
int main()
{
    int i = 0;
    for (i = 100; i <= 999; i++)
    {
        int a = i/100;
        int b = i%100/10;
        int c = i%100%10;
        if (a*a*a + b*b*b + c*c*c == i)
        {
            printf("%d ", i);
        }

    }
    return 0;
}

3.求Sn=a+aa+aaa+aaaa+aaaaa的前5项之和，其中a是一个数字

#define _CRT_SECURE_NO_WARNINGS 1 

#include<stdio.h>
int main()
{
    int sum = 0;
    int a = 0;
    int i = 0;
    int n = 0;
    printf("请输入一一位数字： \n");
    scanf("%d", &a);
    n = a;
    for (i = 0; i < 5; i++)
    {
        sum = sum + a;
        a = 10 * a + n;
    }
    printf("sum = %d\n", sum);
    return 0;
}

4.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 ch, i = 0;
    while ((ch = getchar()) != EOF)
    {
        if (ch == '{')
        {
            i++;
        }
        else if (ch == '}'&&i == 0)
        {
            printf("no\n");
            return 0;
        }
        else if (ch == '}'&&i != 0)
        {
            i--;
        }
    }
    if (i == 0)
        printf("yes\n");
    if (i != 0)
        printf("no\n");
    return 0;
}