C++ Help

[Jean]

hey all, i need your help in this :

i need to write a program that performs the affine cipher
to write a function that takes a text from a .txt file and transform the letters into digits a>0 w b>1 ...

plz i need it ASAP

thx in advance

[Boris®]

mmm, are you taking course cryptography or something ?

its very easy, i think there is a function that transforms ascii to integer, it will be easier than to write if letter=='a' then digit=0, if letter== .....

[Kingroudy]

int i=0;
char str[500];
int strd[500];
ifstream b_file ( "example.txt" );
b_file>>str[0];
while (str[i]!='.')
{
switch (str[i])
{
       case 'a':
       case 'A':
       strd[i]=0;
       break;
// and here u go on and on and on for b and B, c and C...
}
       cout<<strd[i]<<' ';
       i++;
       b_file>>str[i];
       
}

[Jean]

Actually, my friend need help in this, like it is, and i appreciate any help from the members here

[lebanese_a]

Originally Posted by Kingroudy

int i=0;
char str[500];
int strd[500];
ifstream b_file ( "example.txt" );
b_file>>str[0];
while (str[i]!='.')
{
switch (str[i])
{
       case 'a':
       case 'A':
       strd[i]=0;
       break;
// and here u go on and on and on for b and B, c and C...
}
       cout<<strd[i]<<' ';
       i++;
       b_file>>str[i];
       
}

Donno how to work with C++ so I am commenting 7assab ma fhemet the code based on my knowledge of VB.NET

1-" case 'a':
case 'A':"

in VB.NET you can uppercase or lower case the input (UCase, or LCase) that should remove 1 case through the code and make it smaller if it can be done in C++.
if it can't you should write a function (if they exist in C++) that does that, it will come in handy in big apps.

Kamena about the program, why don't you take the ascii chart, and lets say "A"'s ASCII # is 13 (it's not, I am just giving an example) you can make the app take the ascii # and do minus "ASC(A) - 1" ya3neh for A we will have:

Result = 13 (A's number) - 12 (A-1) that will give 1, for B it will be 14 - 12 = 2 w ... this way you could make one very small code and loop it arround the whole text!

[Kingroudy]

the switch case statement is a C++ statement very similar to the if else, so there might be a confusion in the way u understood the code.
and then, i already told john, i did not learn how to do such stuff yet, but i promised him to do something working and i did. I'm sure that it should be done with the ASCII thingy, maybe i can make after some 1 hour of thinking and trying, but he was on a hurry, and i havent learnt those stuff yet.

[Dazlingo]

a switch case ???
lol
just do smth lice c-'a' , where char c="current char"
of course u could use tolower to set them all to lower characters

[Jean]

Originally Posted by Dazlingo

a switch case ???
lol
just do smth lice c-'a' , where char c="current char"
of course u could use tolower to set them all to lower characters

dazlingo, can you please help in this ? i mean can you write it all ?
thx in advance

[ZeRaW]

Originally Posted by Dazlingo

a switch case ???
lol
just do smth lice c-'a' , where char c="current char"
of course u could use tolower to set them all to lower characters

yep this is the correct thinking :P, here ya go:

#include <stdio.h>
#include <conio.h>
#include <ctype.h>
#include <string.h>

void main(void)
{
	FILE * fp = fopen("text.txt","r");
	FILE * outFile = fopen("textout.txt","w");
	//the deal is character 'a' starts at index
	//97 in the ascii set and z is 122
	//so we just do character - 97
	//this wont support characters that are not in the range of 
	//a-z or A-Z
	char c = fgetc(fp);
	while(c != EOF)
	{
		c = tolower(c);
		c -= 97;
		fprintf(outFile,"%i",c);
		c = fgetc(fp);
	}
	fclose(fp);
	fclose(outFile);
}

[Jean]

i need to know where's the mistake in here?

#include
using namespace std;
#include
#include 
using std::ofstream;


//funtion to convert letters into numbers
//function should have the array of numbers as output
void tonumbers(char str[])
{
    int i=0,strd[500];
    

 if(str[i]!=' ')
    {
 switch (str[i])
    {
       case 'a':
       strd[i]=0;
       break;
       cout<>str[0];

    cout<<"enter the multiplier ";
    cin>>mul;
    cout<<"enter the shift key ";
    cin>>key;
    cout<<"enter the plaintext ";
    cin>>plaintext;
    y=tonumbers(plaintext);
    encipher (y);
    


}