Convert Uppercase Letters to Lowercase

Code

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

void to_lowercase(char *str) 
{
    char c;
  while(*str)
  {
    c=*str;
    if(c>=65 && c<=90)
        *str=c+32;

    str++;
  }
}

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;
}

Solving Approach