Encryption program inside...

**abh!shek** · 02-02-2008

Hello,

I know this is a bad program and I have thrown in many bugs related to type conversion. I am getting a warning also. Can you help me correct it ?

Code:

#include<stdio.h>
#include<conio.h>
int main()
{
    char ch[256];
    int cha[256];
    int count;
    printf("Enter a sentence:");
    fgets(ch,256,stdin);
    printf("\n%s",ch);
    for(count=0;ch[count]!='\0';count++)
    {
                                        cha[count]=((int)ch[count]+2);      
    }
    cha[count]=0;
    printf("\n After Encryption:  ");
        /*     for(count=0;cha[count]!=0;count++)
    {
                                      printf("%c",cha[count]);
    }*/
    
    puts((char)cha); /* [Warning] cast from pointer to integer of different size */
    getch();
    return 0;
}

Thank you.

**laserlight** · 02-02-2008

What is this program supposed to do?

**Salem** · 02-02-2008

Print it the same way that you did the original.
It seems to be a string ending in a nul.

**abh!shek** · 02-02-2008

Originally Posted by laserlight

What is this program supposed to do?

Sorry.

It is supposed to take input string and then make it a jumbled secret code. It should add 2 to the ASCII value of each character.

Like A(=97) becomes B (=98).

**laserlight** · 02-02-2008

Okay, so I'm guessing that the reason that you dont want to just do a printf() like earlier in the code is that you want to display the ASCII values of the "encrypted" characters?

**abh!shek** · 02-02-2008

Originally Posted by Salem

Print it the same way that you did the original.
It seems to be a string ending in a nul.

Yes, it is printing a special character (A circle with an arrow pointing downwards) after the encrypted string. But it was doing the same with printf so i commented it out and used puts, thought it would be better to use puts.

**abh!shek** · 02-02-2008

you want to display the ASCII values of the "encrypted" characters?

No I want to display the characters, not their ASCII value.

**abh!shek** · 02-02-2008

If I input ABC it should give CDE.

But it is giving a special character (A circle with an arrow pointing downwards) after the E.

**laserlight** · 02-02-2008

Ah, that is much clearer now.

Basically, you only need one string. You do not need an array of ints. Then you can just write:

Code:

for (count = 0; cha[count] != '\0' && cha[count] != '\n'; count++)
{
    cha[count] += 2;
}
cha[count] = '\0';
printf("\nAfter Encryption: &#37;s", cha);

The catch is that if your string contains the characters '}' or '~', you will end up with unprintable characters.

**Salem** · 02-02-2008

> But it is giving a special character (A circle with an arrow pointing downwards) after the D.
That would be your encrypted version of the \n at the end of the line (as returned by fgets)

Edit:
Beaten.

**abh!shek** · 02-02-2008

Yes its working now. Thanks!

**Abda92** · 02-02-2008

Originally Posted by laserlight

Ah, that is much clearer now.

Basically, you only need one string. You do not need an array of ints. Then you can just write:

Code:

for (count = 0; cha[count] != '\0' && cha[count] != '\n'; count++)
{
    cha[count] += 2;
}
cha[count] = '\0';
printf("\nAfter Encryption: &#37;s", cha);

The catch is that if your string contains the characters '}' or '~', you will end up with unprintable characters.

I think you were supposed to use ch[] not cha[]. And you can fix the problem of non-printable characters by putting an if statement:

Code:

for (count =0; ch[count] != '\0' && ch[count] != '\n'; count++)
{
    if (ch[count] >= sizeof(char) - 2)
        ch[count] -= sizeof(char)-2;
    else
        ch[count] += 2;
}

**abh!shek** · 02-02-2008

Originally Posted by laserlight

The catch is that if your string contains the characters '}' or '~', you will end up with unprintable characters.

Why are } and ~ unprintable ?

**laserlight** · 02-02-2008

Why are } and ~ unprintable ?

They are printable, but when you add 2 to them, the result is not printable.

**abh!shek** · 02-02-2008

Originally Posted by laserlight

They are printable, but when you add 2 to them, the result is not printable.

I still don't get it.
'}' has ASCII value 125.
And 127 is a triangle. So it should print a triangle..

~ has value 126
and 128 is C (not the regular C, it has slightly different shape), so it should print that C....

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