Question

I have two strings, one with an email address, and the other is empty.
If the email adress is e.g. "[e-mail]", I need to pass the start of the email address, just before the @ into the second string. For example:

first string: "[e-mail]"

second string: "abc123"

I’ve written a loop, but it doesn’t work:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main()
{
char email[256] = "[e-mail]";
char temp[256];
int i = 0;

while (email[i] != '@')
{
      temp = strcat(temp, email[i]);
      i++;
}

printf ("%s\n", temp);
system ("PAUSE");
return 0;
}

Basically, I took every time one char from the email address, and added it into the new string. For example if the new string has a on it, now I’ll put b with it too using strcat….

Answer 1

Pointers. Firstly, strcat() returns a char pointer, which C can’t cast as a char array for some reason (which I hear all C programmers must know). Secondly, the second argument to strcat() is supposed to be a char pointer, not a char.

Replacing temp = strcat(temp, email[i]); with temp[i] = email[i]; should do the trick.

Also, after the loop ends, terminate the string with a null character.

temp[i] = '\0';

(After the loop ends, i is equal to the length of your extracted string, so temp[i] is where the terminal should go.)