Strings in C: char Arrays, the Null Terminator and string.h

C has no built-in string type. Strings are just arrays of characters with a special ending.

Direct answer

A C string is a char array that ends with a null terminator ('\0'). Use string.h functions like strlen, strcpy, strcat and strcmp. Always make sure your buffer is large enough, including space for the terminator.

Examples

#include <stdio.h>
#include <string.h>

int main(void) {
    char name[20] = "Ada";
    printf("%s has %zu letters\n", name, strlen(name));

    char copy[20];
    strcpy(copy, name);

    if (strcmp(name, copy) == 0) {
        printf("Same\n");
    }
    return 0;
}

Safe habits

• Size buffers for the longest text plus one.
• Use snprintf for formatting into buffers.
• Never use gets. Use fgets instead.

char line[100];
fgets(line, sizeof(line), stdin);

Where Teyro fits

Teyro's C for Beginners course turns this into short lessons you can play in a few minutes a day. It has 78 lessons, and you can start free.

The bottom line

Remember the null terminator and watch your buffer sizes.

More guides

• malloc and free in C
• Memory Management in C
• Structs in C
• C arrays guide
• C for Beginners course