string to int

BadTaste · 08-17-2004, 08:44 AM

hello

I'm coding an encryption algorithm and need to go from a string of text to there integer representation to encrypt them. using getline is a good way of getting the string so is there a function that would translate this to an int and then back to the string after decryption.

rkdugar · 08-17-2004, 09:17 AM

You can use the function "atoi()" to convert the string to int and you can use "itoa()" to convert int to string in C.

Cheers,

rkdugar

BadTaste · 08-17-2004, 09:33 AM

i might be doing something wrong but atoi doesnt work. its ok if your changing a number string to an integer but not a string made up of letters. all i seem to get back is 0

itsme86 · 08-17-2004, 10:03 AM

Quote:

Originally posted by BadTaste
i might be doing something wrong but atoi doesnt work. its ok if your changing a number string to an integer but not a string made up of letters. all i seem to get back is 0

How else would it work? What does your encryption string look like? Are there other symbols besides letters? Do the non-numeric characters have a set number associated with them? I'm confused as to what you're actually looking for.

deiussum · 08-17-2004, 10:06 AM

So you want the ASCII representation of each character? Just cast each individual char to an int.

For example:

Code:

 #include <iostream>

 using namespace std;

 int main()
 {
    char str[6]="Hello";

    for (int c=0;c<5;c++)
    {
        cout << (int)str[c] << endl;
    }
 }

Results:

72
101
108
108
111

Kumar · 08-17-2004, 10:14 AM

atoi is used to convert "1234" to 1234 and won't take anything else as argument. What are u exactly trying to acheive?

BadTaste · 08-17-2004, 11:51 AM

what i am trying to do is read in a line of text from a file convert it to its integer so hello would be 072101108108111 and then get back to hello. i was hoping their might be a function that could do that or i might be using the string to int functions wrong. if not then the only other way i can see would be to read in a char at a time convert to its integer check if it is less than 100 if it is add a 0 so "a" = 097 then place that in a string go to the next char b = 098 and so on until the end of the line. then convert that string 097098 to a number and thats the number that is encrypted. for me the first way would be a bit easier

itsme86 · 08-17-2004, 12:08 PM

Code:

$ cat cvr.c
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

int main(void)
{
  char str[6] = "Hello", *s, chstr[4];
  char buf[100] = "", *b;
  char recon[6];

  for(s = str, b = buf;*s;s++, b += 3)
    sprintf(b, "%03d", *s);

  printf("Converted: %s\n", buf);

  chstr[3] = '\0';
  for(b = buf, s = recon;*b;b += 3, s++)
  {
    strncpy(chstr, b, 3);
    *s = atoi(chstr);
  }
  recon[5] = '\0';

  printf("Reconstructed: %s\n", recon);

  return 0;
}

...gives me...

Quote:

$ ./cvr
Converted: 072101108108111
Reconstructed: Hello

Is that what you're looking for?

BadTaste · 08-17-2004, 12:26 PM

that should help thanks

The_Nerd · 08-18-2004, 12:16 AM

Lol! This guy is funny!

The_Nerd · 08-18-2004, 12:17 AM

Guess I shouldn't say that though... he might be a newb... sorry!

djgerbavore · 08-18-2004, 10:23 AM

if you want to convert a string to a int. in java there is hashcode in hte string class.

for example

Code:

                string str = "hello";
                int strInteger = str.hashCode();

this will convert this str in its integer representation. for example

Code:

(((((72 x 10^4)+((((68x10^3))+(((76x10^2)))+((76x10^1)))) + (79x10^0))))).

this will give you unqiue interger representation of the string hello.
for encryption and decryption hashcode are the way to go.

to convert it back to a string its just as easier, converto byteArray and then to string.
let me know if this was helpful