/* Homework 1 for Allen Holub's C for Professionals class.  September, 1990.
   By Ronald E. Jacobs. */

/* adjust(str, col) */

/* STR is a null terminated string of characters.  A word is any 
group of characters not 
separated by a space.  Spaces trailing a word are 
treated as part of that word.  Spaces leading the first word 
are treated as part of the first word.  Adjust distributes additional
spaces as evenly 
as is possible between words and without regard to original spacing,
so that the last character of the last 
word ends in column COL.  If spaces cannot be added equally between 
words then the modulo of excess spaces is added, one space each, 
between words from the left end of STR until the excess is exhausted.  
The string is modified in place.  If STR contains no words or one word, 
ADJUST does nothing.  ADJUST prints an error message if COL is less 
than the number of characters in STR. */ 

#define YES 1
#define NO  0
#include <math.h>
#include <stdio.h>

#define DEBUG NO	/* YES to compile debugging statements, else NO */

int nchar, nword, inword, gap[75]; 

adjust(str, col)
char	str[];
int	col;
{
	printf("\n                 1         2         3");
	printf("\ncolumn: 123456789012345678901234567890");
	printf("\ninput:  ");
	puts(str);		/* print unmodified string */
	cntwords(str);		/* count characters and words and locate gaps */
	fixstr(str, col);	/* adjust the string in place */
	printf("output: ");
	puts(str);		/* print modified string */
	return;
}


/* Count the number of characters and words in the string str. */
/* Put into gap[] the character position number following the end of each word. */

cntwords(str)
char	str[];
{
	nchar = nword = 0;
	inword = NO;

	for(nchar = 0; str[nchar]; nchar++){
		if(str[nchar] == ' '){
			inword = NO;
			continue;
		}
		else if(!inword){ 
			inword = YES;
			++nword;
			if(nword >= 2){
				gap[nword-2] = nchar;
#if DEBUG
	printf("\ncharacter count is: %-4u for array subscript %-4u",
		gap[nword - 2], nword - 2);
#endif
			}
		}
	}
#if DEBUG
	printf("\ntotal character count is: %-4u \n", nchar);
	printf("\nword count is: %-4u ", nword);
#endif
	return;
}


/* Do in place adjustment of string */
fixstr(str, col)
char	str[];
int	col;
{
	int wholsp, modsp, nsp, i;
	int spadded, curgap, nspace, gaps;
	
	if(col < nchar){
		printf("\nadjust error: more characters than columns");
		return;
	}
	if(nword < 2){
		return;	               /* no adjustment necessary */	
	}
	gaps = (nword - 1);            /* number of gaps between words */
	wholsp = (col - nchar)/(gaps); /* number of spaces to add per gap */
	modsp = col - nchar - gaps * wholsp;  /* remainder of spaces to
						add in gaps */
#if DEBUG
	printf("\nnumber of gaps is: %-4u ", gaps);
	printf("\nspaces to add per gap is: %-4u ", wholsp);
	printf("\nremainder of spaces to add in gaps is: %-4u ", modsp);
#endif
	spadded = 0;	          /* number of spaces added in previous gaps */

	for (i = 0 ; i < gaps; ++i){
		nspace = wholsp;
		if (modsp){
			++nspace;    /* spaces to add in this gap */
			--modsp;  /* remaining remainder spaces */
		}
		curgap = gap[i] + spadded; /* location of current gap*/
		
		spadded += nspace;	/* location of next gap after adjusting
				           this gap */
#if DEBUG
	printf("\nthis gap is number: %-4u ", i);
	printf("\ncurrent gap location is: %-4u ", curgap);
	printf("\nnumber of spaces to add in this gap is: %-4u ", nspace);
#endif
		for ( ;nspace; --nspace){
			addsp(str, curgap);	/* insert a single space */
		}
	}
	return;
}

/* Add a ' ' into a null terminated array.  Put the ' ' into position
   array[charnum] and shift all bytes from the original byte at
   array[charnum] up to and including the null termination right one byte. */

addsp(str, curgap)
char	str[];
int	curgap;
{
	char temp1, temp2;

	temp1 = ' ';
	
	for ( ; ; ){
		temp2 = str[curgap];	/* temporarily save current character */
		str[curgap] = temp1;	/* put old character in new position. */
		if (!temp1){		/* if character is a null */
			break;
		}
		++curgap;		/* work on next character in string */
		temp1 = temp2;		/* was current character, now old */
	}
	return;
}