C strings are arrays of characters ending with a null terminator.

Character Arrays

char_arrays.c
#include <stdio.h>

int main(void) {
    char word[4] = {'c', 'a', 't', '\0'};
    char first = ;

    word[0] = first;

    printf("word=%s\n", word);
    return 0;
}
#include <stdio.h>

int main(void) {
    char word[4] = {'c', 'a', 't', '\0'};
    char first = ;

    word[0] = first;

    printf("word=%s\n", word);
    return 0;
}
#include <stdio.h>

int main(void) {
    char word[4] = {'c', 'a', 't', '\0'};
    char first = ;

    word[0] = first;

    printf("word=%s\n", word);
    return 0;
}
null terminator The `'\0'` character marks where a C string ends.
mutable characters Changing one array element changes the visible string content.