can someone explain why output is 5. and not 6 ?

Question

#include <iostream>
#include <string>
using namespace std;

int main() {
int a=5;
int b=1<--a;// 1
int c=1+--a;// 5
int d=1+b*c;
// Output 5
cout<<d;
return 0;
}

Answer 1

int c = 1 + --a;

The value of `a` before this line was 4. On reaching this line it become 3, so 1 + 3 = 4. That is why value of `c` is 4 not 5.

This itself further explains your question.

Answer 2

Thanks 👍