A constant is a value that does not change during a particular operation, while a literal is a value written directly in the source code. C provides different forms of literals for integers, floating-point values, characters, and strings.

#include <stdio.h>

int main()
{
    int decimal = 100;
    int octal = 0144;
    int hexadecimal = 0x64;

    float temperature = 25.5f;
    char letter = 'A';

    printf("Decimal      = %d\n", decimal);
    printf("Octal        = %d\n", octal);
    printf("Hexadecimal  = %d\n", hexadecimal);
    printf("Temperature  = %.1f\n", temperature);
    printf("Letter       = %c\n", letter);

    return 0;
}

Example Output #

Decimal      = 100
Octal        = 100
Hexadecimal  = 100
Temperature  = 25.5
Letter       = A

Explanation #

An integer literal can be written using different number bases:

int decimal = 100;
int octal = 0144;
int hexadecimal = 0x64;

All three represent the same numeric value, 100, but use different representations.

A floating-point literal can include a suffix:

float temperature = 25.5f;

The f suffix specifies a float literal.

A character literal is enclosed in single quotes:

char letter = 'A';

A string literal is enclosed in double quotes:

"Hello"

String literals are covered in greater detail in the Strings module.

Common Literal Types #

A character constant such as 'A' has type int in C, although it is commonly stored in a char object.