The if statement

Learn how to check a condition with if and the code block.

The if statement

To run certain code when a condition is true you use the if statement. The condition is written inside parentheses and, if true, the block wrapped in braces runs: if (age >= 18) { std::cout << "Can drive"; }.

C++ does not use a then keyword; the parentheses and the brace block are enough. The condition must evaluate to a bool value, which the comparison operators produce. When the condition is false the block is skipped and the program moves to the next statement.

Comparison operators

Inside if conditions you often use comparison operators. == is equal, != is not equal, < is less than, > is greater than, <= is less than or equal, >= is greater than or equal.

Note: = is assignment and == is comparison. If you write if (count = 0) you reset count to zero and the result is false, so the block does not run. Always use double == for comparison.

Exercise Age check

The age variable is set to 20. Use the condition if (age >= 18) to check whether the age is 18 or above and, if true, print "Can drive".

Show example solution

#include <iostream>

int main() {
    int age = 20;
    if (age >= 18) {
        std::cout << "Can drive" << std::endl;
    }
    return 0;
}

Test yourself

Which is a valid if statement?
```
if (... ) { ... }
```
- if (age >= 18) { ... }
- if age >= 18 { ... }
- if (age >= 18) then { ... }
- if [age >= 18] { ... }
Show answer

if (age >= 18) { ... } — The condition is in parentheses; no 'then' keyword.

Write the if condition

int age = 20;
if (____) { std::cout << "Access granted"; }

Show answer

int age = 20;
if (age >= 18) { std::cout << "Access granted"; }

Match each operator to its meaning

==

Equal
!=

Not equal
<

Less than
>=

Greater or equal

Next lesson: else and else if

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