菱形和水仙花数

1.在屏幕打印菱形（n=7）;

include <stdio.h>int main(){    int n; int i=0;int j=0;    printf("input n\n");    scanf("%d", &n);    //打印上边部分    for (i= 0; i < n; i++){        for (j = 0; j < n - 1 - i; j++){            printf(" ");        }        for (j = 0; j <1 +2* i; j++){            printf("*");        }            printf("\n");    }}   // 打印下半部分   for (i = 1; i < n; i++){       for (j = 0; j <i ; j++){        printf("");    }       for (j = 0; j <2*n-2*i-1 ; j++){        printf("*");    }    printf("\n");}return 0;}#2.计算10000以内所有水仙花数  #include<stdio.h>

include

3.求Sn=a+aa+aaa+aaaa+aaaaa的前5项之和，其中a是一个数字，例如：2+22+222+2222+22222include

#include<stdio.h>int main(){int i = 0;int a = 0;int sum = 0;int num=0;scanf("%d",&num);   //输入数字元素for (i = 0; i < 5; i++){a = a * 10 + num;//观察得到sum = sum + a;}printf("%d", 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>include<windows.h>  //system("pause")的头文件int main(){     char ch;     int count = 0;     while ((ch = getchar()) != EOF){                  if ( (ch) == '{'){                                count++;         }         if ((ch) =='}'&&count == 0){                       printf("花括号不匹配");             return 0;         }         if ((ch) == '}'){                                count--;         }     }     if (count == 0){                                    printf("花括号匹配\n");     }     else {         printf("花括号不匹配\n");     }    system("pause");    return 0;    }