Write a program to encode text and to decode the encoded text.

Perfrom the encoding saccording to these replacements

\(\begin{array}{c c c c c c c c c c c c c c c c c c c c c c c c c c} a&b&c&d&e&f&g&h&i&j&k&l&m&n&o&p&q&r&s&t&u&v&w&x&y&z \\ m&n&k&g&h&d&t&a&b&w&v&u&p&r&q&c&z&j&x&i&e&y&f&l&o&s\end{array}\)

Example:
plain text: Program
Encoded text: Cjqtjmp
Decoded text: Program

#include <stdio.h>
#include <string.h>
#include <conio.h>
#define SIZE 100
 
void main()
{
	char plain[SIZE], encoded[SIZE], decoded[SIZE];

	// the matching1 array contains the correspondance between the plain text and
	// the encoded text. Example, 'm' will be in place of 'a' and so on
	// matching2 array is the correspondance between the encoded and decoded text
	char matching1[26]={'m','n','k','g','h','d','t','a','b','w','v','u','p','r','q','c','z','j','x','i','e','y','f','l','o','s'};
	char matching2[26]={'h','i','p','f','u','w','d','e','t','r','c','x','a','b','y','m','o','n','z','g','l','k','j','s','v','q'};
    	int i;
 
	printf("Enter  a string : ");
	gets(plain);	
 
	// we loop on the plain text
    	for(i=0; plain[i]!='\0'; i++)
		// in case the character is a lower case
		// we retreive the index of matching1 by substracting 'a'
		// Example, if plain[i] is equal to 'b', 'b'-'a' will
		// be equal to 1 and thus, we get the corresponding character 
		// in matching1 at index 1.
		if(plain[i]>='a' && plain[i] <='z')
			encoded[i]=matching1[plain[i]-'a'];
		else
			// if the character is an upper case, we do the same,
			// to get the correspondance, however the array stores 
			// lowercase correspondance, we need to convert it to
			// uppercase. it suffices to substract 'a' and add 'A'
			encoded[i]=matching1[plain[i]-'A']-'a'+'A';
	encoded[i]='\0';

    	for(i=0; encoded[i]!='\0'; i++)
		if(encoded[i]>='a' && encoded[i] <='z')
			decoded[i]=matching2[encoded[i]-'a'];
		else
			decoded[i]=matching2[encoded[i]-'A']-'a'+'A';
	decoded[i]='\0';

	printf("Plain text: %s\n", plain);
	printf("Encoded text: %s\n", encoded);
	printf("Decoded text: %s\n", decoded);
	getch();
}