char *string_toupper(char *s)
{
int i;
while( s[i] != ' ' )
{
// if character is in lowercase
// then subtract 32
if( s[i] >= 'a' && s[i] <= 'z' )
{
s[i] = s[i] - 32;
}
// increase iterator variable
i++;
}
return (s);
}