Upper/Lower Case in C

gistfile1.c

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

char *uppercase( char str[256] );
char *lowercase( char str[256] );

main(){
	char str[256] = "";
	
	printf("Please Enter Your Name Fully\t");
	scanf("%s", str);

	printf("Upper Case: %s \t", uppercase( str ) );
 	printf("Lower Case: %s", lowercase( str ) );
}


//to convert any string to upper case
char *uppercase( char str[256] ){
	int i;
	
	for( i = 0; i < strlen(str); i++ ){
		str[i] = toupper(str[i]);
	}
	
	return str;
}

//to conver any string to lowercase 
char *lowercase( char str[256] ){
	int i;
	
	for( i = 0; i < strlen(str); i++ ){
		str[i] = tolower(str[i]);
	}
	
	return str;
}