Comparison operators
- C++ course
- Beginner
- Lesson 26/116
- 4 min
Learn to compare values with ==, !=, <, >, <= and >=.
Comparison operators
Comparison operators compare two values and return a bool (true/false). Six operators: == (equal), != (not equal), < (less), > (greater), <= (less or equal), >= (greater or equal).
Note: == is comparison, = is assignment. if (x == 5) checks whether x equals 5; if (x = 5) assigns 5 to x and is always true. This is a very common mistake.
Since the result is bool, it can be stored in a variable: bool same = (a == b);. When printed with std::cout, true shows as 1, false as 0.
Comparison results
A comparison result is true or false. std::cout prints them as 1 and 0. To see the text true/false, use std::boolalpha.
Examples: 5 < 10 → true, 5 > 10 → false, 5 == 5 → true, 5 != 5 → false.
Comparisons are mostly used in if conditions: if (age >= 18). But they can also be assigned to a variable and used later. This is useful for breaking down complex conditions.
Practice Print comparison results
Inside main, declare int a = 10; and int b = 20;. Perform two comparisons: bool first = a < b; and bool second = a == b;. Print both on separate lines with std::cout using std::endl.
Starter code
#include <iostream>
int main() {
// Declare a and b
// Do two comparisons and print them
return 0;
}Sample solution
#include <iostream>
int main() {
// Declare a and b
int a = 10;
int b = 20;
// Do two comparisons and print them
bool first = a < b;
bool second = a == b;
std::cout << first << std::endl;
std::cout << second << std::endl;
return 0;
}Expected output
1 0
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 Equality comparison
bool same = (a ____ b);bool same = (a == b);Explanation: == is the equality comparison.
2 What is the result of 5 != 3?
- 0 (false)
- 3
- 1 (true) Correct answer
- 5
Explanation: 5 and 3 are not equal, so the result is true (1).
3 Match comparison operators
| Term | Meaning |
|---|---|
== |
Equal |
!= |
Not equal |
< |
Less |
>= |
Greater or equal |