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A little Encryption / Decryption Program !

CMinus (70)
Hello all , Today I tried to make a little Encryption / Decryption program that its en/decryption depends on an array of numbers (repeated when the last element of it is reached )
What ever the problem is With Switch , If & getline function !! because when I remove them it works great !!
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#include <iostream>
#include <string>
using namespace std;
void encrypt(char a[],int x);
void decrypt ( char b[],int x);
	string texttest ;
	char *a;
	

  
void textinput()
{
	
getline(cin, texttest);
a=new char[texttest.size()+1];
a[texttest.size()]=0;
memcpy(a,texttest.c_str(),texttest.size());
	
}

int main ()
{
	
	int choice;
	cout<<"Choose 1 to encrypt , 2 to decrypt";
	cin>>choice;
	
	if(choice ==1){
	cout<<"Enter a message to encrypt : ";
	textinput();
	encrypt(a,texttest.size());}
	else if(choice ==2)
	{	cout<<"Enter a message to encrypt : ";
	textinput();
	decrypt(a,texttest.size());}
	else cout<<"Run The app again";


	
	
	system("PAUSE") ;
  return 0;
}
void encrypt ( char b[],int x)
{int num;
int keyindex;
int key [3] = {1,2,3};
for (num=0 ,keyindex=0 ; num<x;num++,keyindex++)
  {
	if(keyindex==3)
keyindex=0;
	
b[num]= b[num]+ key[keyindex];
cout<<b[num];


  }
}
void decrypt ( char b[],int x)
{int num;
int keyindex;
int key [3] = {1,2,3};
for (num=0 ,keyindex=0 ; num<x;num++,keyindex++)
{if(keyindex==3)
keyindex=0;
	b[num]= b[num]- key[keyindex];
cout<<b[num];
}


}

My first code trial !! didn't work !!
CMinus (70)
Would any one Help me , Please ??
CMinus (70)
It has been two days since i posted and no answers ??? Please give me a hand here !!
cire (8284)
You haven't said what's wrong, and the formatting of the code is horrid. The driver doesn't give any result you can see, so assuming it compiles, I don't know how you'd know whether it worked or not.

Please read http://www.cplusplus.com/forum/beginner/1/
Particularly the "When you ask" portion.

CMinus (70)
Sorry my mistake !!
When I compile the code above , it skips the getline statement
and here is the result 


Choose 1 to encrypt , 2 to decrypt1
Enter a message to encrypt : Press any key to continue . . .


but when I remove the conditional if it works greatly like that 
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int main ()
{
	
	
	cout<<"Enter a message to encrypt : ";
	textinput();
	encrypt(a   ,   texttest.size()  ); ;
	system("PAUSE") ;
  return 0;
}



and here is the result after removing the conditional If

Enter a message to encrypt : my name
n{#ocpf // this is the encrypted msg!
Press any key to continue . . .


And about the format it looks okay for me !! I don't know why u see it's horrid :)
And Thanks for help !!
cire (8284)
You use cin to extract an int from the stream. When you do this (maybe by typing in the equivalent of "1\n") the 1 is extracted, but the newline remains in the stream. So, when you get to textinput() there is a dangling newline waiting to feed your getline().

One solution would be to change textinput() to resemble the following:

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void textinput()
{
	if ( cin.peek() == '\n' )
		cin.get() ;

	getline(cin, texttest);

	a=new char[texttest.size()+1];
	a[texttest.size()]=0;
	memcpy(a,texttest.c_str(),texttest.size());
}


Btw, Dqgf"lt"kptujdoz"iptpbvwff1
Last edited on
CMinus (70)
Thanks dude it works now , although I didn't understand the use of cin.peek() ( I will search it later I have to go to maths lecture now ) !!
And about the Formatting I will try to reformat it :):)
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