what is wrong with my code? it shows runtime error

include<iostream>

using namespace std; int main() {int t,a,b,i,c; cin>>t; if(t>=1&&t<=100) { for(i=0;i<t;i++) cin="">>a>>b; if(a>b) c=a; else c=b; return(c,a+b); } else return 0; }