Standard Size of character (\'a\') in C/C++ on Linux

In C, every character including 'a' is stored using a specific size in memory. On most systems including Linux, the size of a character is 1 byte. This means that any character (like 'a') occupies 1 byte (8 bits) of memory.

To determine how much memory is used by the character 'a', we can use the sizeof() operator, which returns the size in bytes of a variable or data type.

Syntax

sizeof(expression)
sizeof(datatype)

Method 1: Using sizeof with Character Literal

This approach checks the size of the character literal 'a' using the sizeof() operator −

#include <stdio.h>

int main() {
    printf("Size of character 'a' = %zu byte\n", sizeof('a'));
    return 0;
}

Size of character 'a' = 1 byte

Method 2: Using sizeof with char Variable

Here, we declare a variable of type char and then use sizeof() to determine its size −

#include <stdio.h>

int main() {
    char ch = 'a';
    printf("Size of char variable 'ch' = %zu byte\n", sizeof(ch));
    return 0;
}

Size of char variable 'ch' = 1 byte

Method 3: Using sizeof with Pointer to char

When we declare a pointer to a character and check its size, it shows the size of the pointer itself, not the character −

#include <stdio.h>

int main() {
    char *ptr;
    printf("Size of char pointer = %zu byte(s)\n", sizeof(ptr));
    printf("Size of char data type = %zu byte\n", sizeof(char));
    return 0;
}

Size of char pointer = 8 byte(s)
Size of char data type = 1 byte

Method 4: Checking ASCII Value and Size

We can also check the ASCII value of a character while confirming its size. The ASCII value of 'a' is 97 −

#include <stdio.h>

int main() {
    char ch = 'a';
    printf("Character: %c\n", ch);
    printf("ASCII Value: %d\n", ch);
    printf("Size: %zu byte\n", sizeof(ch));
    return 0;
}

Character: a
ASCII Value: 97
Size: 1 byte

Key Points

• The char data type in C is guaranteed to be exactly 1 byte on all systems.
• Use %zu format specifier for sizeof() results to ensure portability.
• Pointer size depends on the system architecture (8 bytes on 64-bit systems).

Conclusion

In C, the character 'a' and all other characters consistently occupy 1 byte of memory. The sizeof() operator is the standard way to verify memory usage of any data type or variable.