What did I do wrong here?

Question

Idid this
#include <iostream>
using namespace std;

//change
int main() {

int a;
int b;
int sub = a-b;

cout <<"Cash" <<endl;
cin >>a;

cout <<"Cost" <<endl;
cin>> b;

cout <<"The change is:" <<sub <<endl;

return 0;
}

Answer 1

when you declarete the variable sub you puts the value of null because you tried to quit none units to a none value
int a;
int b;
int sub=a-b;
now a=0 and b=0 and 0-0=0
to solve this you only need to declarete the variable sub whit any value and at the end of getting input puts the value of sub like this

int main (){
int a;
int b;
int sub;

cout <<"something"<<endl;
cin>>a;
cout <<"other thing"<<endl;
cin>>b;
sub=a-b;
cout <<sub <<endl;
return 0;
}

Answer 2

nothing here any errors..
good... keep it up!

Answer 3

Ah, ok thanks. I thought it was wrong because the app doesn't run it properly...but thank you

Answer 4

Oh, it's true. Now it works. Thank you.