Basic C language series-four implementation methods for returning string functions

There are four methods: 1. Use the heap space and return the requested heap address. Pay attention to Release 2. Function parameters pass a pointer and 3 is returned. Returns the static variable (SHARE) 4 defined in the function. Return the global variable ****************** from csdn **************** * ************* is actually to return a valid pointer, the tail variable is invalid after exiting.

Use the allocated memory. The address is valid.
Char * Fun ()
{
Char * s = (char *) calloc (100, sizeof (char *));
If (s)
Strcpy (S, "ABC ");
Return S;
}
However, in this way, you must use this method to free up the returned address.

input the address from the input parameter
char * Fun (char * s)
{< br> If (s)
strcpy (S, "ABC");
return s;
}< br> note that the size allocated to S is sufficient when calling this method.
you can do this:
char * Fun (char * s, int Len)
{< br> If (s)
{< br> strncpy (S, "ABC", len-1);
S [len-1] = 0;
}< br> return S;
}

Or use local static variables
Char * Fun ()
{
Static char s [100];
Strcpy (S, "ABC ");
Return S;
}
Do not modify the returned string in this way. Because it is a shared address, the modification will be reflected to each caller. You can do this:
Const char * Fun ()
{
Static char s [100];
Strcpy (S, "ABC ");
Return S;
}

Another way is to use global variables.
Char G_s [100];
Char * Fun ()
{
Strcpy (G_s, "ABC ");
Return S;
}
Pay attention to the maximum storage space of this variable.