从C ++程序调用linux命令

Question

I write the following simple c++ program in order to learn about how to call Linux command from C++ program (by using the system command)

Please advice why I have the errors from the C++ compiler? what wrong with my program?

more exm2.cc

#include <stdio.h>
#include <stdlib.h>
int main()
{
  system("echo -n '1. Current Directory is '; pwd");
  system("mkdir temp");
  system();
  system();
  system("echo -n '3. Current Directory is '; pwd");
  return 0;
  }


  [root@linux /tmp]# g++ -Wall  exm2.cc  -o exm2.end

  /usr/include/stdlib.h: In function גint main()ג:
  /usr/include/stdlib.h:738: error: too few arguments to function גint system(conג
  exm2.cc:7: error: at this point in file
  /usr/include/stdlib.h:738: error: too few arguments to function גint system(conג
  exm2.cc:8: error: at this point in file

Answer 1

You can't use system() without a char* parameter.

So these statements are wrong :

system();
system();

If you are not going to make anything, just don't put anything in there.

Answer 2

system() takes at one argument you could call it with an empty string:

#include <stdio.h>
#include <stdlib.h>
int main()
{
  system("echo -n '1. Current Directory is '; pwd");
  system("mkdir temp");
  system("");
  system("");
  system("echo -n '3. Current Directory is '; pwd");
  return 0;
  }

But you may as well just leave those lines out :-)

Answer 3

the system() function requires a parameter. Try removing the 7th and 8th line.

#include <stdio.h>
#include <stdlib.h>
int main()
{
  system("echo -n '1. Current Directory is '; pwd");
  system("mkdir temp");
  system("echo -n '3. Current Directory is '; pwd");
  return 0;
}

Answer 4

system takes a const char* . You call it 5 times, passing nothing to it twice.