Sir, why does it shows three red cross marks with wrong answer message even though when the output is right

#1

#include<bits/stdc++.h>
using namespace std;

int rep(int n)
{
int fs=0,sum=0,ld,fd;
while(n>0)
{
ld=n%10;
if(ld==0)
{
ld=5;
sum=sum10+ld;
}
else
{
sum=sum10+ld;
}
n=n/10;
}
while(sum>0)
{
fd=sum%10;
fs=fs*10+fd;
sum=sum/10;
}
return fs;
}

int main()
{
int num=102;
cout << rep(num);
return 0;
}