10.27

while练习

#include<stdio.h>
int main(void)
{
    int a,count,sum;
    float ave;
    printf("请输入一个数字\n");
    scanf("%d",&a);
    sum = a;
    count = 1;
    while(a !=0){
        printf("请输入一个数字\n");
        scanf("%d",&a) ;
        sum = a+ sum;
        count = count + 1; 
    } 
    count = count - 1;
    ave = sum /(float)count;
    printf("ave = %f",ave);
    return 0;
}

do-while

do{程式片段}while(表示式);

a第一次无论（ ）中成不成立，都会做一次{ }中的片段

#include<stdio.h>
int main(void)
{
    int a = 9;
    int b;
    do {
        printf("猜一个数字：");
        scanf("%d",&b);
        if(a > b)
        printf("too small\n");
        else if(a < b)
            printf("too largr\n");
        else 
            printf("correct\n");
    } while(a != b);
    return 0;
}

复合赋值运算

switch do-while混合练习

#include<stdio.h>
int main(void)
{
    int total = 0;
    int id;
    do {
        printf("输入商品数：");
        scanf("%d",&id);
        switch (id){
          case 1:total = total + 90;
          break;
          case 2:total = total + 80;
          break;
          case 3:total = total + 70;
          break;
          case 4:total = total + 60;
          break;
          }
       } while(id != 0);
       printf("共计：%d",total);
        return 0;
}

for

for (初始式;条件式;回圈式){程式片段}

先执行初始式

当条件式成立时，执行{ }。否则就结束回圈

先执行一次回圈式后，在判断条件式是否成立

#include<stdio.h>
int main(void)
{
    int a = 1;
    for(a = 1;a <= 10;a++){
        printf("%d\n",a);
    }
    return 0;
}

#include<stdio.h>
int main(void)
{
    int a = 1;
    for(a = 1;a <= 10;a++){
        printf("%d\n",a);
    }
    return 0;
    }