Answer 1

The tolower() function takes an uppercase alphabet and convert it to a lowercase character.

#include <stdio.h>
#include <ctype.h>
int main()
{
char c, result;

c = 'M'; result = tolower(c); printf("tolower(%c) = %c\n", c, result);

c = 'm'; result = tolower(c); printf("tolower(%c) = %c\n", c, result);

c = '+'; result = tolower(c); printf("tolower(%c) = %c\n", c, result); return 0;
}

Output
tolower(M) = m
tolower(m) = m
tolower(+) = +