Strings

Strings are nothing more than arrays of characters, with a null
character at the end, '\0'.

string-building.c

#include <stdio.h>

void hard( void ) {
    char hello[6];
    hello[0] = 'H';
    hello[1] = 'e';
    hello[2] = 'l';
    hello[3] = 'l';
    hello[4] = 'o';
    hello[5] = '\0';

    printf( "%s\n", hello );
}

void easy( void ) {
    char world[] = "world";
    printf( "%s\n", world );
    printf( "world[] is %lu bytes\n", sizeof( world ) );
}

int main( void ) {
    hard();
    easy();

    return 0;
}

$ string-building

Hello
world
world[] is 6 bytes