K&R2 Exercise 3-2

3-2.c

/*K&R2 Exercise 3-2 "escape"*/

#include <stdio.h>

#define MAX_LINE 1024

int getl(char[], int);
void escape(char[], char[]);
void unescape(char[], char[]);

int main()
{
	char s[MAX_LINE];
	char t[MAX_LINE];

	while(getl(t, MAX_LINE)){
		escape(s, t);
		printf("Escaped: %s\n", s);
		unescape(t, s);
		printf("UnEscaped: %s", t);
	}
}

int getl(char s[], int lim)
{
	int c, i;

	for(i = 0; i < lim-1 && (c = getchar()) != EOF && c !='\n'; ++i)
		s[i] = c;
	if(c == '\n')
		s[i++] = c;
	s[i] = '\0';
	return i;
}

void escape(char s[], char t[])
{
	int i, j;
	for(i = 0, j = 0; t[i] != '\0'; i++){
		if(t[i] == '\n'){
			s[j++] = '\\';
			s[j++] = 'n';
		}
		else if(t[i] == '\t'){
			s[j++] = '\\';
			s[j++] = 't';
		}
		else
			s[j++] = t[i];
	}
}

void unescape(char s[], char t[])
{
	int i, j;
	for(i = 0, j = 0; t[i] != '\0'; i++) {
		if(t[i] == '\\' && t[i+1] == 'n') {
			s[j++] = '\n';
			i++;
		}
		else if(t[i] == '\\' && t[i+1] == 't') {
			s[j++] = '\t';
			i++;
		}
		else
			s[j++] = t[i];
	}
}