关于#c++#的问题，请各位专家解答！

#include<bits/stdc++.h>
using namespace std;
int a,b;
int mina,minb,houra,hourb;
int main(){
    scanf("%d%d",&a,&b);
    mina=a%100;
    minb=b%100;
    houra=(a-mina)/100;
    hourb=(b-minb)/100;
    if(minb<mina){
        minb+=60;
        hourb--;
    } 
    int hour=hourb-houra;
    int mint=minb-mina;
    if(hour<10){
        printf("0");
    }
    printf("%d:",hour);
    if(mint<10){
        printf("0");
    }
    printf("%d",mint);
    return 0;
}