为什么算出来结果是0?
#include <stdio.h>int money=0;int distance(int n,int t1,int t2){ if(n<=3) { money=13*2; } else if(t1>=23&&t2<=5) { money=13*2+(n-3)*2.3*(1+0.2)*2; } else { money=13*2+(n-3)*2.3*2; } return money;}int main(){ distance(12,6,9); money=money+2; printf("所需费用为%f元",money); return 0;}