K&R C Exercise 1-19 Solution

/*
 * Exercise 1-19 Write a function reverse(s) that reverses
 * that character string s. Use it to write a program that
 * reverses its input a line at a time.
 *
 * fduan, Dec. 11, 2011 
 */
#include <stdio.h>

#define MAX_LEN 1000

int getline( char line[], int max_len );
void reverse( char line[] );

int main()
{
	char line[MAX_LEN];
	int len;

	while( ( len = getline( line, MAX_LEN ) ) > 0 )
	{
		if( len > 0 )
			reverse( line );
		printf( "%s", line );
	}
	
	return 0;
}

int getline( char line[], int max_len )
{
	int c, i, j;
	
	i = j = 0;

	while( ( c = getchar() ) != EOF && c != '\n' )
	{
		if( i < max_len - 2 )
			line[j++] = c;
		++i;
	}

	if( c == '\n' )
	{
		line[j++] = c;
		++i;
	}

	line[j] = '\0';

	return i;
}

void reverse( char line[] )
{
	int i, j;
	char tmp;

	i = j = 0;
	while( line[j] != '\n' )
		++j;
	
	for( --j; i < j; ++i, --j )
	{
		tmp = line[i];
		line[i] = line[j];
		line[j] = tmp;
	}
}