Caesar Encryption Problem Program

Design idea: The process of encrypting is to move the letter in the alphabet two bits backwards, i.e. A programming D, string +3, decrypted string -3 ;

Program Flowchart:

Source:

Wang Zhewen Caesar problem encryption and decryption key: Encryption is a string +3, decryption time-3

Package string11;

Import Java.util.Scanner;

public class Jiami

{

public static void Main (string[] args) throws Exception

{

TODO auto-generated Method Stub

System.out.println ("[A encryption] [J decryption],please Choose one");

Scanner s=new Scanner (system.in);//Create Scanner Object

String S1=s.nextline ();//Get the bank string

if (S1.equalsignorecase ("a"))//Determine the size of S1 and a

{

int key;

System.out.println ("Please enter clear text:");

Scanner sc=new Scanner (system.in);

String Ss=sc.nextline ();

System.out.println ("Please enter key:");

Scanner scc=new Scanner (system.in);

Key=scc.nextint ();//convert input characters to int type

Encryption (Ss,key);//Call encryption method

}

else if (s1.equalsignorecase ("J"));

{

int key;

System.out.println ("Please enter ciphertext:");

Scanner sc=new Scanner (system.in);

String SS =sc.nextline ();

System.out.println ("Please enter key:");

Scanner scc=new Scanner (system.in);

Key=scc.nextint ();

Decrypt (Ss,key);//Call encryption method

}

}

Encryption Program

public static void encryption (String str,int t)

{

String string= "";

int i;

char c;

For (I=1;i<str.length (); i++)

{

C=str.charat (i);

if (c>= ' a ' &&c<= ' z ')//If a character in a character is lowercase

{

C+=t% 26;///Move 26 bit

if (c< ' a ')

c+=26;//to the Zou world

if (c> ' z ')

c-=26;//Right over bounds

}

else if (c>= ' a ' &&c<= ' Z ')//If one of the characters in the character is uppercase

{

C+=t% 26;

if (c< ' A ')

c+=26;//to the Zou world

if (c> ' Z ')

c-=26;//Right over bounds

}

String +=c;//the encrypted character into a string

}

SYSTEM.OUT.PRINTLN (str + "after encryption:" + string);

}

public static void Decrypt (String str,int N)

{

int t;

T=integer.parseint ("-" +n);

String string= "";

int i;

For (I=0;i<str.length (); i++)

{

Char C=str.charat (i);

if (c>= ' a ' &&c<= ' z ')//If a character in a character is lowercase

{

C+=t% 26;//Move 26 bit

if (c< ' a ')

c+=26;//to the Zou world

if (c> ' z ')

c-=26;//Right over bounds

}

else if (c>= ' a ' &&c<= ' Z ')//If one of the characters in the character is uppercase

{

C+=t% 26;

if (c< ' A ')

c+=26;//to the Zou world

if (c> ' Z ')

c-=26;//Right over bounds

}

String +=c;//the encrypted character into a string

}

SYSTEM.OUT.PRINTLN (str + "after decryption:" + string);

}

}

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Caesar Encryption Problem Program