C++: "Transportation" Test

Question

I don't know why this code won't work. (Assume that x=231. And please look carefully.)

#include <iostream>
using namespace std;

int main() {
//your code goes here
int x;
int y=50;
int z=y-(x%y);
cin>>x;
if (x<=y){
cout<<y-x<<endl;
}
else{
cout<<y-(x%y);
}
return 0;
}

At first, I used the Z value in the "else" curly brackets, but then since that didn't work, I typed out the whole thing instead. It worked this time. So why didn't Z's value (which is the exact same thing) work with 231, but typing out its full value did?

Edit: Sorry, okay, I was pretty confused at first as to what I had to do, so I ended up using if...else since that was the first thing that came to mind.

Answer 1

1. You don't need the if else statement at at. 1 line is all you need after getting the number of passengers.
2. How do you expect this line to work;
int z=y-(x%y);
when you are getting the value for x after it and not before?
FYI, the r-value of that statement is all you need to output.

Answer 2

Koloroj

Why you are writing if else even you can get solution in few lines.

Just do

int seats = 50 - passengers % 50;

cout << seats;

Where passengers is input.