96. Convert Uppercase Letters to Lowercase

#include <stdio.h>
#include <stdint.h>

bool is_upper_alpha(char c){
    return 'A' <= c && c <= 'Z';
}
void to_lowercase(char *str) {
    int i = 0;
    while (str[i] != '\0') {
        if (is_upper_alpha(str[i])){
            str[i] += 'a' - 'A';
        }
        i++;
    }
}

int main() {
    char str[101];
    fgets(str, sizeof(str), stdin);

    // Remove newline
    uint8_t i = 0;
    while (str[i]) {
        if (str[i] == '\n') {
            str[i] = '\0';
            break;
        }
        i++;
    }

    to_lowercase(str);
    printf("%s", str);
    return 0;
}