#include <stdio.h>

// The size of character arrays that we will use to store strings.
#define BUFSIZE 500

// Remove any leading spaces from string.
static void
remove_leading_spaces(char *string)
{
	char *s;

	// Make s point at the first non-space character
	for (s = string; *s == ' '; s++)
		;

	if (s == string)
		// There are no leading spaces so simply return
		return;

	// Now work forward through the string, copying each
	// character to an earler position.
	while (*s != '\0')
		*string++ = *s++;

	// Mark the new end of the string
	*string = '\0';
}

// Remove any spaces from the end of the string
static void
remove_trailing_spaces(char *string)
{
	// ADD CODE HERE
	char *s;

	// Make s point at the first non-space character
	for (s = string; *s != '\0'; s++);

	//to go backwards till we find a non " "
	
	for(s--;*s==' ';s--);
	// jump forward one, so to access the first " " and set it to the end of the line \0 marker
		s++;
		*s='\0';


	if (s == string)
		// There are no trailing spaces so simply return
		return;

}

// Replace any sequence of 2 or more space characters by a single space.
static void
remove_repeated_spaces(char *string)
{

// ADD CODE HERE

char *s;
char *n;
s = string;
n = string;

	while (*s != '\0')
	{
		*n = *s++;
		if ((*n == ' ') && (*s == ' '))
		{
			while (*s != '\0')
			*string++ = *n++;
		}
		else
		{
			s++;
			n++;
		}
		//s++;
		//n++;
	}

	if(s == string)
		return;

}

// Read a line of input from the standard input and return 3 copies
// of it in s1, s2 and s3. zero is returned if successful, -1 if
// the input is at end-of-file.
static int
get_test_strings(char *s1, char *s2, char *s3)
{
	// read a line to a maximum of BUFSIZE into the first string
	if (fgets(s1, BUFSIZE, stdin) == NULL)
		return -1;

	// Copy the first string into the other two strings.
	// Do not copy any trailing linefeed or carriage-return
	while (*s1 != '\0' && *s1 != '\n' && *s1 != '\r')
		*s3++ = *s2++ = *s1++;

	// terminate the two strings
	*s3 = *s2 = *s1 = '\0';
	return 0;
}

int
main(int argc, char **argv)
{
	char buf1[BUFSIZE], buf2[BUFSIZE], buf3[BUFSIZE];
	
	printf("Test string:");
	while (get_test_strings(buf1, buf2, buf3) == 0) {
		remove_leading_spaces(buf1);
		remove_trailing_spaces(buf2);
		remove_repeated_spaces(buf3);
		printf("\twith leading spaces removed '%s'\n", buf1);
		printf("\twith trailing spaces removed '%s'\n", buf2);
		printf("\twith repeated spaces removed '%s'\n", buf3);
		printf("Test string:");
	}
	printf("\n");
	return 0;
}