Question

Possible Duplicate:
concatenate char array in C

How to concatenate:

char *a="abcd";
char *b="1234";

using the strcat()? And answer to the same when user enters *a and *b?

EDIT missed out this: without using another array.

Answer 1

You can’t monkey around with the string literals you’ve already initialized – they’re sitting somewhere in memory & can’t/shouldn’t be rewritten.

If you don’t want another statically-defined array but don’t mind dynamic allocation, the code below may accomplish what you’re looking for:

char *a = "abcd";
char *b = "1234";
char *out;

if((out = (char *)malloc(strlen(a) + strlen(b) + 1)) != NULL)
{
   strcpy(out, a);
   strcat(out, b);
}
else
{
   //you don't have enough memory, handle it
}

If that’s still unacceptable, consider a different approach to initializing your string literals.