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

#define LENGTH 1000
#define MAXLINE 32
#define SCREEN_WIDTH 80

void promptString(const char * prompt, char * response);
void readWords(char words[][MAXLINE], int * numWords);
void selectionSort(char words[][MAXLINE], int numWords);
void swap(char * str1, char * str2);
int longestWord(const char words[][MAXLINE], int numWords);
int wordsPerLine(int width);
void printWords(const char words[][MAXLINE], int numWords);
void printOne(const char * word, int width);

int main()
{
	int numWords;
	char words[LENGTH][MAXLINE]; //an automatic array of strings, this is not the norm

	readWords(words, & numWords);
	printWords(words, numWords);
	selectionSort(words, numWords);
	printWords(words, numWords);

	return 0;
}

void readWords(char words[][MAXLINE], int * numWords)
//precondition: input is open and ready to read; words is completely allocated 
{
	*numWords = 0;

	printf("Enter a word [EOF to quit]: ");
	while(scanf("%s", words[*numWords]) == 1)
	{
		++*numWords;

		printf("Enter a word [EOF to quit]: ");
	}
}

void selectionSort(char words[][MAXLINE], int numWords)
{
	int i, j, min;
	for(i = 0; i < numWords - 1; i++)
	{
		min = i;
		for(j = i + 1; j < numWords; j++)
		{
			if(strcmp(words[j], words[min]) < 0)
				min = j;
		}

		if(min != i)
			swap(words[i], words[min]);
	}
}

void swap(char * str1, char * str2)
//precondition: str1 and str2 are not NULL and have enough memory allocated
{
	char temp[MAXLINE];
	
	strcpy(temp, str1);
	strcpy(str1, str2);
	strcpy(str2, temp);
}

int longestWord(const char words[][MAXLINE], int numWords)
//returns index of longest string found in words, returns -1 if words is empty
{
	if(numWords == 0)
		return -1;
	else
	{
		int k;
		int max = 0;
		for(k = 0; k < numWords; k++)
			if(strlen(words[k]) > strlen(words[max]))
				max = k;

		return max;
	}
}

int wordsPerLine(int width)
//assuming 80 char lines in display, return number of words that could fit
{
	return SCREEN_WIDTH/width;
}
	
void printWords(const char words[][MAXLINE], int numWords)
//output words left to right, formatted to width of 
{
	int k;
	int maxLen = strlen(words[longestWord(words, numWords)]);
	int lineCount = wordsPerLine(maxLen + 1); //space between each word

	for(k = 0; k < numWords; k++)
	{
		printOne(words[k], maxLen);
		if(lineCount != 0 && (k+1) % lineCount == 0)
			printf("\n");
	}
	printf("\n");
}

void printOne(const char * word, int width)
//output word left justified in width wide character spaces
{
	int numSpaces = width - strlen(word) + 1;
	int k;

	printf("%s", word);
	for(k = 0; k < numSpaces; k++)
		printf(" ");
}