If the linewidth is set at say 80, and the 80th character is in the middle of a word, the entire word must be put on the next line. So as you're scanning, you have to remember the position of the end of the last word that didn't go over 80 characters.
So here is mine, it's not clean; I've been breaking my head for the past hour trying to get it to work, adding something here and there. It works for all edge cases that I know of.
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
int isDelim(char c){
switch(c){
case '\0':
case '\t':
case ' ' :
return 1;
break; /* As a matter of style, put the 'break' anyway even if there is a return above it.*/
default:
return 0;
}
}
int printLine(const char * start, const char * end){
const char * p = start;
while ( p <= end )
putchar(*p++);
putchar('\n');
}
int main ( int argc , char ** argv ) {
if( argc <= 2 )
exit(1);
char * start = argv[1];
char * lastChar = argv[1];
char * current = argv[1];
int wrapLength = atoi(argv[2]);
int chars = 1;
while( *current != '\0' ){
while( chars <= wrapLength ){
while ( !isDelim( *current ) ) ++current, ++chars;
if( chars <= wrapLength){
if(*current == '\0'){
puts(start);
return 0;
}
lastChar = current-1;
current++,chars++;
}
}
if( lastChar == start )
lastChar = current-1;
printLine(start,lastChar);
current = lastChar + 1;
while(isDelim(*current)){
if( *current == '\0')
return 0;
else
++current;
}
start = current;
lastChar = current;
chars = 1;
}
return 0;
}
So basically, I have start and lastChar that I want to set as the start of a line and the last character of a line. When those are set, I output to standard output all the characters from start to end, then output a '\n', and move on to the next line.
Initially everything points to the start, then I skip words with the while(!isDelim(*current)) ++current,++chars;. As I do that, I remember the last character that was before 80 chars (lastChar).
If, at the end of a word, I have passed my number of chars (80), then I get out of the while(chars <= wrapLength) block. I output all the characters between start and lastChar and a newline.
Then I set current to lastChar+1 and skip delimiters (and if that leads me to the end of the string, we're done, return 0). Set start, lastChar and current to the start of the next line.
The
if(*current == '\0'){
puts(start);
return 0;
}
part is for strings that are too short to be wrapped even once. I added this just before writing this post because I tried a short string and it didn't work.
I feel like this might be doable in a more elegant way. If anyone has anything to suggest I'd love to try it.
And as I wrote this I asked myself "what's going to happen if I have a string that is one word that is longer than my wraplength" Well it doesn't work. So I added the
if( lastChar == start )
lastChar = current-1;
before the printLine() statement (if lastChar hasn't moved, then we have a word that is too long for a single line so we just have to put the whole thing on the line anyway).
I took the comments out of the code since I'm writing this but I really feel that there must be a better way of doing this than what I have that wouldn't need comments.
So that's the story of how I wrote this thing. I hope it can be of use to people and I also hope that someone will be unsatisfied with my code and propose a more elegant way of doing it.
It should be noted that it works for all edge cases: words too long for a line, strings that are shorter than one wrapLength, and empty strings.
