c how to program 习题4.19

//C how to program 习题4.19
//功能：计算零售额
#include<stdio.h>
int main(void){
    //打印产品零售价
    printf("%s", "产品编号\t\t零售价\n");
    printf("%5d\t\t\t$%.2f\n", 1, 2.98);
    printf("%5d\t\t\t$%.2f\n", 2, 4.50);
    printf("%5d\t\t\t$%.2f\n", 3, 9.98);
    printf("%5d\t\t\t$%.2f\n", 4, 4.49);
    printf("%5d\t\t\t$%.2f\n", 5, 6.87);
    //定义变量
    int number=0;
    float price, salesVolume, retailValue=0.0;
    //获取要计算的产品编号
    printf("\n请输入产品编号1-5:");
    scanf("%d", &number);
    //当用户输入有误，要求重新输入
    while(number<1 || number>5){
        printf("\n输入错误，没有这个产品编号！请重新输入产品编号1-5:");
        scanf("%d", &number);
    }
    //根据产品编号获取产品零售价
    switch( number )
    {
        case 1:
            price = 2.98;
            break;
        case 2:
            price = 4.50;
            break;
        case 3:
            price = 9.98;
            break;
        case 4:
            price = 4.49;
            break;
        case 5:
            price = 6.87;
            break;

    }
    //获取上周每天的销量
    for(int i=0; i<7; i++){
        printf("请输入星期%d的请销量：", i+1);
        scanf("%f", &salesVolume);
        retailValue += salesVolume;
    }
    //输出计算结果
    printf("\n编号为%d的产品上周销量为%.2f,单价是%.2f,销售额是%.2f", number, retailValue, price, retailValue*price);
}