（使用if-else述句）对多个变数求最大值的练习

#include <stdio.h>
int main()
{
    int a,b,c,max;
    printf("Please enter three integers: ");
    scanf("%d%d%d",&a,&b,&c);
    if (a >= b && a >= c)
    {
        max = a;
    }else if (b >= a && b >= c)
    {
        max = b;
    } else {
        max = c;
    }
    printf("The maximum ids %d.", max);
    return 0;
}

 switch 述句

switch (整数值)  {
    case 常数整数值:
         程式片段;
         break;
    default:
         程式片段;
         break;

}

如：

#include <stdio.h>
int main()
{
    int id;
    printf("ID: ");
    scanf("%d",&id);
    switch (id)
    {
    case 2:
        printf("John
");
        break;
    case 13:
        printf("Mary
");
        break;
    default:
        printf("Not found
");
        break;
    }
    return 0;


}

 练习：消费金额计算的练习（使用switch述句）

#include <stdio.h>
int main()
{
    int total = 0;
    int id;
    do{
            scanf("%d", &id);
    switch (id) {
        case 1: total += 90; break;
        case 2: total += 75; break;
        case 3: total += 83; break;
        case 4: total += 89; break;
        case 5: total += 71; break;

    }
        }while (id != 0);
        printf("Total: %d
", total);
        return 0;


}