What is the difference between ++i and i++ in C++?
There is a big distinction between the suffix and prefix versions of ++.
- In the prefix version (i.e., ++i), the value of i is incremented, and the value of the expression is the new value of i. So basically it first increments then assigns a value to the expression.
- In the postfix version (i.e., i++), the value of i is incremented, but the value of the expression is the original value of i. So basically it first assigns a value to expression and then increments the variable.
Example
Let's look at some code to get a better understanding −
#include<iostream>
using namespace std;
int main() {
int x = 3, y, z;
y = x++;
z = ++x;
cout << x << ", " << y << ", " << z;
return 0;
}
Output
This would give us the output −
5, 3, 5
Why is this? Let's look at it in detail −
- Initialize x to 3
- Assign y the value we get by evaluating the expression x++, ie, the value of x before increment then increment x.
- Increment x then assign z the value we get by evaluating the expression ++x, ie, value of x after the increment.
- Print these values
Published on 15-Feb-2018 16:22:51