#include <stdio.h>
#include <string.h>
#include <stdlib.h>

char *toLower(char *str);

int main(void)
{
	char str[]="HELLO, WORLD";
	char *strp;

	printf("Before toLower (%s)\n", str);
	strp = toLower(str);
	printf("After  toLower (%s)\n", strp);

	return 0;
}

char *toLower(char *str)
{
	char *retp, *retp0;
	retp = (char *)malloc(strlen(str));
	retp0 = &retp[0];

	for ( ; *str ; *retp++, *str++){
		*retp = *str;
		if ( 'A' <= *str && *str <= 'Z' )
			*retp += 0x20;
	}
	return retp0;
}