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Ceaser.java
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Ceaser.java
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import java.util.*;
class Ceaser
{
public static void main(String[] args)
{
Scanner sc = new Scanner(System.in);
System.out.println("Enter Plain Text:");
String in = sc.nextLine();
System.out.println("Enter Key:");
int key =sc.nextInt();
System.out.println("What You want to Do??\n1.Encryption\t2.Decryption\t3.Exit");
boolean p=true;
while(p)
{
int op=sc.nextInt();
switch(op)
{
case 1:System.out.println("Cipher Text is:"+Ceaser.encrypt(in,key));break;
case 2:System.out.println("Plain Text is:"+Ceaser.decrypt(Ceaser.encrypt(in,key),key));break;
case 3:System.exit(0);
}
}
}
public static String encrypt(String in,int key)
{
String alphaU="ABCDEFGHIJKLMNOPQRSTUVWXYZ";
String alphaL="abcdefghijklmnopqrstuvwxyz";
String op="";
for(int i=0;i<in.length();i++)
if(in.charAt(i)>=65 &&in.charAt(i)<=90)
op+=alphaU.charAt((alphaU.indexOf(in.charAt(i))+key)%26);
else
op+=alphaL.charAt((alphaL.indexOf(in.charAt(i))+key)%26);
return (op);
}
public static String decrypt(String op,int key)
{
String alphaU="ABCDEFGHIJKLMNOPQRSTUVWXYZ";
String alphaL="abcdefghijklmnopqrstuvwxyz";
String op1="";
for(int i=0;i<op.length();i++)
{
if(op.charAt(i)>=65 &&op.charAt(i)<=90)
{
if(alphaU.indexOf(op.charAt(i))-key<0)
op1+=alphaU.charAt(((alphaU.indexOf(op.charAt(i))-key)+26)%26);
else
op1+=alphaU.charAt((alphaU.indexOf(op.charAt(i))-key)%26);
}
else
{
if(alphaU.indexOf(op.charAt(i))-key<0)
op1+=alphaL.charAt(((alphaL.indexOf(op.charAt(i))-key)+26)%26);
else{
op1+=alphaL.charAt((alphaL.indexOf(op.charAt(i))-key)%26);}
}
}
return op1;
}
}