Printing all environment variables in C / C++

#include <stdio.h>

extern char **environ;

int main() {
  char **s = environ;

  for (; *s; s++) {
    printf("%s\n", *s);
  }

  return 0;
}

The environment variables are made available to main() as the envp argument - a null terminated array of strings:

int main(int argc, char **argv, char **envp)
{
  for (char **env = envp; *env != 0; env++)
  {
    char *thisEnv = *env;
    printf("%s\n", thisEnv);    
  }
  return 0;
}