I wrote a program several years ago that I run every day.
   I wanted to make a small change to it, but then it would not compile.
   This is strange because I simply changed a value (from 20 to 30), which
   should not have any effect on whether it compiles or not. But now
   it does not compile! It did compile a few years ago, and now it does not.
   There are likely several things that have changed since.

   Here is a short program that demonstrates the same problem.

carmaux:~$ cat strcpy_err.cpp 

#include <iostream>
#include <iomanip>
#include <fstream>
#include <stdio.h>
#include <stdlib.h>
#include <string>

using namespace std;

main(int pcount, char *params[])
{
    char fname1[512];

    fname1[0] = '\0';

    if (pcount >= 2) 
       strcpy(fname1, params[1]);

    cout << "first parameter is " << fname1 << endl;

    return(0);
}

carmaux:~$ g++ strcpy_err.cpp 
strcpy_err.cpp: In function `int main(int, char**)':
strcpy_err.cpp:22: error: `strcpy' was not declared in this scope
carmaux:~$

   Now I'll make a change to fix it...
     
carmaux:~$ cat strcpy_err.cpp
#include <iostream>
#include <iomanip>
#include <fstream>
#include <stdio.h>
#include <stdlib.h>
#include <cstring>

using namespace std;

main(int pcount, char *params[])
{
    char fname1[512];

    fname1[0] = '\0';

    if (pcount >= 2) 
       strcpy(fname1, params[1]);

    cout << "first parameter is " << fname1 << endl;

    return(0);
}

carmaux:~$ g++ strcpy_err.cpp 
carmaux:~$ ./a.out hello
first parameter is hello

  I made a simple change, and then it compiled.
  The change was in the include of "cstring" instead of "string". 
  Changing "string.h" would have also worked.

--
Michael Weeks, copyright 2012