Hey friends please explain me this code and say why its output is ab?

Question

#include <iostream>
using namespace std;
char Blackbox(char &ch){
int x=-1;
if(x++>x)
return ch++;
else
return ch--;

}
int main() {
char ch1='b';
char ch2=Blackbox(ch1);
cout<<ch1<<ch2;

return 0;
}
// output is 'ab' ?

Answer 1

ok, couple of things to note here:
1) x++>x evaluates to false, because increment is done first, so both values are equal
2) return ch-- returns current ch, and AFTERWARDS ch gets decremented
3) char &ch means pass by reference, that's why ch1 is changed from b to a (decrement after return on ch1)
4) ch2 gets the returned value, which was b

So the output is ab

If you change ch-- to --ch, the output would be aa

If you change x++>x to x+1>x , you will land in the first branch of if-else-statement. Same rules apply here, only with increment instead of decrement