in-place conversion of string from snake case to camel case

snake_to_camel.c

// SPDX-License-Identifier: Unlicense
// Author: Derrick Lyndon Pallas <derrick@pallas.us>

#include <stdbool.h>
#include <ctype.h>

char *
snake_to_camel(char * string) {
    bool upper = true;
    char * camel = string;
    for (const char * snake = string ; *snake ; ++snake) {
        if (isalpha(*snake)) {
            *camel++ = upper ? toupper(*snake) : tolower(*snake);
        } else if (isdigit(*snake)) {
            *camel++ = *snake;
        }
        upper = !isalpha(*snake);
    }
    *camel = '\0';
    return string;
}