# C Programming — The if Statement

> A basic C example demonstrating comparison operators, conditional execution, else, the modulo operator and block syntax.

- Author: Muhammet Ali Köker
- Language: en
- Canonical: https://alikoker.com.tr/en/c-programming-if-statement
- Translation: https://alikoker.com.tr/c-if-yapisi
- Published: 2013-07-20T13:00:00+03:00
- Modified: 2026-08-08T13:49:35+03:00
- Verified: 2026-08-07T11:00:00+03:00
- Type: article

The `if` statement is used when an operation should be performed only when a specified condition is satisfied.

```c
#include <stdio.h>
#include <conio.h>
int main()
{
int number1, number2;
printf("Enter two numbers:\n");
scanf("%d %d", &number1, &number2);
if ( number1 == number2 )
printf("%d is equal to %d\n", number1, number2);
if ( number1 != number2 )
printf("%d is not equal to %d\n", number1, number2);
if ( number1 < number2 )
printf("%d is less than %d\n", number1, number2);
if ( number1 > number2 )
printf("%d is greater than %d\n", number1, number2)
if ( number1 <= number2 )
printf("%d is less than or equal to %d\n", number1, number2);
if ( number1 >= number2 )
printf("%d is greater than or equal to %d\n", number1, number2);
if ( number1 % 2 == 0)
printf("number1 is even");
else
printf("number1 is odd");
getch();
return 0;
}
```

- The conditions use parentheses and compare two variables with the comparison operators `==`, `!=`, `<`, `>`, `<=` and `>=`.

- There are two possible outcomes. When the condition is true, the statement after `if` is executed; otherwise it is skipped. For a single statement this continues up to the terminating semicolon. Multiple statements must be placed between braces `{` and `}`.

- Notice that comparison uses two equals signs (`==`). A single equals sign (`=`) is the assignment operator and is not used for equality comparison.

- The percent sign (`%`) performs the modulo operation. If the result is zero, the number is evenly divisible. In this example, a true condition prints that `number1` is even.

- When the condition is false, the statement after `else` is executed, so the program prints that `number1` is odd.

- Also notice that no semicolon is placed immediately after the `if` or `else` keywords.

## References

- **[1]** Brian W. Kernighan; Dennis M. Ritchie. (1988). The C Programming Language, Second Edition. Prentice Hall.
- **[2]** International Organization for Standardization. (2011). ISO/IEC 9899:2011 - Programming Languages - C. ISO.

## Cite This Work

Köker, M. A. (2013). C Programming — The if Statement. alikoker.com.tr. https://alikoker.com.tr/en/c-programming-if-statement

- BibTeX: https://alikoker.com.tr/en/c-programming-if-statement.bib
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