为什么会是0分啊？

#include<stdio.h>
#include <math.h>
int main()
{
    int T,a;
    double m = 3.141593;
    scanf("%d", &T);
    if (T == 1)
        printf("I love Luogu!");
    if (T == 2)
        printf("%d %d", 6, 4);
    if (T == 3)
        printf("%d\n%d\n%d", 3, 12, 2);
    if (T == 4)
        printf("%3f", 500 / 3);
    if (T == 5)
        printf("%d", (260 + 220) / (12 + 20));
    if (T == 6)
        printf("%lf", sqrt(6 * 6 + 9 * 9));
    if (T == 7)
        printf("%d\n%d\n%d", 110, 90, 0);
    if (T == 8)
        printf("%lf\n%lf\nlf",2*5*m,5*5*m,m*5*5*5*3/4);
    if (T == 9)
        printf("%d", 22);
    if (T == 10)
        printf("%d", 9);
    if (T == 11)
        printf("%lf", 100 / 3);
    if (T == 12)
        printf("%d\nR", 13);
    if (T == 13)
        a = pow(4*4*m+10*10*m,1.0/3);
        printf("%d", a);
    if (T == 14)
        printf("%d", 50);
    return 0;
}