八、循环

#include <stdio.h>
 
int main()
{
    int sum = 0;
    int count = 0;
    int number;
 
    scanf("%d", &number);
    while ( number != -1 ) {
        sum += number;
        count ++;
        scanf("%d", &number);
    }
 
    double dsum = sum;
    printf("The average is %f.\n", dsum / count);
 
    return 0;
}

#include <stdio.h>
 
int main()
{
    int n = 3;
 
    while ( n>= 0 ) {
        printf("%d ", n);
        n--;
    }
    printf("发射\n");
 
    return 0;
}

#include <stdio.h>
 
int main()
{
    int number = rand()%100+1;
    //rand()可以得到一个随机的整数
 
    int count = 0;
    int a = 0;
    printf("我已经想好了一个1到100之间的数。");
    do {
        printf("请猜这个1到100之间数：");
        scanf("%d", &a);
        if ( a > number ) {
            printf("你猜的数大了。");
        } else if ( a < number ) {
            printf("你猜的数小了。");
        }
        count ++;
    } while (a != number);
    printf("太好了，你用了%d次就猜到了答案。\n", count);
 
    return 0;
}

#include <stdio.h>
 
int main()
{
    int n;
    int i;
    double ret=0.0;
 
    scanf("%d", &n);
    for ( i=1; i<=n; i++ ) {
        ret += 1.0/i;
    }
    printf("%f\n", ret);
 
    return 0;
}