switch语句

#include <stdio.h>
int main()
{
    float s, y, w, h;
    float z;
    int select;
    s = 138.5;
    y = 89.5;
    w = 110;
    h = 99.5;
    scanf("%d", &select);

    switch (select)
    {
        case 1:
        printf("chengji shi %3.1f\n", s);
        break;
        case 2:
        printf("chengji shi %3.1f\n", y);
        break;
        case 3:
        printf("chengji shi %3.1f\n", w);
        break;
        case 4:
        printf("chengji shi %3.1f\n", h);
        break;
        default:
        z = s + y + w + h;
        printf("z shi %3.1f\n", z);
        break;
    }
}