A simple substitution cipher can be created by shifting a le

A simple substitution cipher can be created by shifting a letter n positions in alphabetic order. For example, if the possible characters are the list [A…Za…z], a shift of three would translate A to D and Z to c. The shift is circular so z would shift around to C. The shift value, n, can be positive or negative.

Write c/c++ program that performs this simple substitution cipher. Your c/c++ program should request the user to enter a shift value, followed by one alphabetic character. It should then print the cipher text for that character. Print an appropriate error message if the user enters something other than a letter from the list [A…Za…z].

Solution

#include <stdio.h>

int main() {
   char ch;
   int value,e,fvalue=0;

   printf(\"enter one alphabetic character\ \");
   scanf(\"%c\",&ch);
   if(ch>=65 && ch<=90 && ch>=97 && ch<=122)
   {
   printf(\"enter the shift value\ \");
   scanf(\"%d\",&value);
   e=ch;
   fvalue=e+value;
   if(fvalue>90)
   {
   fvalue=fvalue+7;
   }
   printf(\"cipher text is:%c\",fvalue);
   fvalue=0;
   }
   else
   {
   printf(\"wrong input\");
   }
   return 0;
}