Using variables in system() function c++

Question

  string line;
  ifstream myfile (\"aaa.txt\");
  getline (myfile,line);
  system(\"curl.exe -b cookie.txt -d test=\"+line+\"  

        

Answer 1

Problem 1:

Your problem stems from the fact that system is of signature:

int system (const char *command);

What you have is of type std::string.

One way to fix this is to build a new std::string and then get the char pointer using c_str().

string cmd("curl.exe -b cookie.txt -d test=");
cmd += line;
cmd += "  http://example.com";

Then pass the content to system.

system(cmd.c_str());

Problem 2:

Reading data and passing it unvalidated and unclean to system will allow anyone using your program to run commands at the shell.

This is a security risk.