Listing 3

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

main()
{
  char *pc;
  char string[21];

  while (scanf("%20s", string) != EOF) {
     pc = getenv(string);
     if (pc == NULL)
        printf("no such string defined\n");
     else
        printf("%s defined as >%s<\n", string, pc);
  }
}



                 Output

path
path defined as >c:\dos;c:\util;<
Path
Path defined as >c:\dos;c:\util;<
PATH
PATH defined as >c:\dos;c:\util;<
xyz
no such string defined