Run-error is occurred again and again

#1

everytime i run my code run error is occurred.
what is the main reason for this and how can it be resolved.

#2

Hey @Mudit809
Can you post your code?

#3

this is the code and run error is occurring.

#include
#include
#include
#include

using namespace std;

int mycompare(string x, string y){

string xy= x.append(y);


string yx= y.append(x);

return xy.compare(yx) > 0 ? 1: 1;

}

void printlargest(vector arr, int n ){

sort(arr.begin(), arr.end(), mycompare);

for(int i=0; i<n ; i++)
cout<<arr[i];

cout<<endl;

}

int main(){
int t;
vector arr;

string temp;
long long n;
cin>>t;
while(t--){
cin>>n;
for(int i=0;i<n;i++){
	cin>>temp;
	arr.push_back(temp);
	
}

printlargest(arr , n);

}
return 0;
}