ex 4

#include <stdio.h>
#include <math.h>

void encrypt(int num)
{
    int length = -1;
    int num_copy = num; // a number to measure the length
    int num_left_to_right;
    int current_num;

    while(num_copy != 0)
    {
        length++;
        num_copy /= 10;
    }

    while(length > -1)
    {
        num_left_to_right = num * pow(10, (-1) * (length));
        current_num = num_left_to_right % 10;

        if(current_num ==  0)
            current_num = 8;

        else if(current_num == 1)
            current_num = 9;

        else
            current_num -= 2;

        printf("%d", current_num);
        length--;
    }
}


void main()
{
    encrypt(12034);
}