Ex_1.19_reversestr.c

/**
 * Exercise 1.19 - Write a function reverse that reverses the character
 * string s; use it to write a program that reverses its input a line at a time.
 *
 **/

#include<stdio.h>

#define MAXLINE 1000

int mgetline(char line[], int lim);

void reverse(char rline[]);


int main(void)
{
	int len;
	char line[MAXLINE];

	while((len = mgetline(line, MAXLINE)) > 0 )
	{
		reverse(line);
		printf("%s",line);
	}

	return 0;
}


int mgetline(char s[],int lim)
{
	int i,c;
	
	for(i=0; i<lim-1 && (c=getchar()) != EOF && c != '\n'; ++i)
		s[i] = c;

	if( c == '\n')
	{
		s[i] = c;
		++i;
	}
	s[i] = '\0';

	return i;
}


void reverse(char rline[])
{
	int i,j;
	char temp;

	for(i=0;rline[i]!='\0';++i)
		;

	--i;

	if(rline[i]=='\n') --i;

	j = 0;

	while(j < i)
	{
		temp = rline[j];
		rline[j] = rline[i];
		rline[i] = temp;
		--i;
		++j;
	}
}