/*
 * Program to read line of text and print in reverse,
 * several ways.
 */
#include <stdio.h>
#include <string.h>

#define SIZE 80

void print_line(char * line);
void print_reverse_1(char * line);
void print_reverse_2(char * line);
void reverse_line(char * line);

int main(void) {
	printf("enter line of text:\n");
	char line[SIZE];
	fgets(line, sizeof(line), stdin);
	/* was the line too long? */
	char *endline = strchr(line, '\n');
	if (endline == NULL) {
		printf("line too long\n");
	}
	else {
		*endline = '\0';
		puts("original line");
		print_line(line);
		print_reverse_1(line);
		print_reverse_2(line);
		puts("line after reverse in place");
		reverse_line(line);
		print_line(line);
	}
	return 0;
}

void print_line(char * line) {
	printf("'%s'\n", line);
}

void print_reverse_1(char * line) {
	puts("line in reverse, one way:");
	putchar('\'');
	for (int i = strlen(line)-1; i >= 0; --i) {
		putchar(line[i]);
	}
	putchar('\'');
	putchar('\n');
}
void print_reverse_2(char * line) {
	puts("line in reverse, another way:");
	putchar('\'');
	for (char * p = line + strlen(line)-1; p >= line; --p) {
		putchar(*p);
	}
	putchar('\'');
	putchar('\n');
}
void reverse_line(char * line) {
	char * left = line;
	char * right = line + strlen(line) - 1;
	while (left < right) {
		char temp = *left;
		*left = *right;
		*right = temp;
		left += 1;
		right -= 1;
	}
}