自己写的程序，不能

#include<stdio.h>
int main(void)
{
    int i,a;
    printf("[1]Select crisps\n[2]Select popcorn\n[3]Select chocolate\n[4]Select cola\n[0] Exit\n");
    for(i=1;i<=5;i++)
    {
        printf("Enter a number of food:");
        scanf("%d",&a);
        if(a>=0&&a<=4)
        {
            switch(a)
            {
                case 1:printf("prise is 3.0");break;
                case 2:printf("prise is 2.5");break;
                case 3:printf("prise is 4.0");break;
                case 4:printf("prise is 3.5");break;
                case 0:break;
            }
        }
        else
        printf("prise is 0.0\n");
    }
    printf("thanks\n");
}