How to call a script from inside CPP code in linux - c++

Question

I am new to C++ coding using linux.Hence, my apologies if my question is trivial.
I need some help regarding calling some script/executable from inside a cpp file.
I downloaded few libraries (Blas, Lapack, libtsnnls-2.3.3). Configured and made executable. This executable was created when I configured and compiled libtsnnls-2.3.3.
I can call from command line:
cd /home/dkumar/libtsnnls-2.3.3/tsnnls
./genb_test
Now, I want to call the same command from a cpp file. It's something similar to "HelloWorld.cpp"
My Attempt (modified based on suggestion of #Biffer #timrau:
// 'Hello World!' program
#include <stdio.h> /* defines FILENAME_MAX */
#include <cstdlib> /* MODIFIED std::system */
#include <iostream>
#ifdef _MSC_VER
#include "direct.h"
#define GetCurrentDir _getcwd // window ??
#else
#include "unistd.h"
#define GetCurrentDir getcwd
#endif
int main()
{
std::cout << "Hello World!" << std::endl;
// const char *ParentFolder = "/home/dkumar/All_Matlab_Codes_DKU";
const char *ParentFolder = "/home/dkumar/libtsnnls-2.3.3/tsnnls/";
int res3 = chdir(ParentFolder);
// exceuting the command('./genb_test')
std::system('./genb_test');
return 0;
}
I get the following errors:
HelloWorld.cpp:36:10: warning: character constant too long for its type [enabled by default]
system('./genb_test');
^
HelloWorld.cpp: In function ‘int main()’:
HelloWorld.cpp:36:23: error: invalid conversion from ‘int’ to ‘const char*’ [-fpermissive]
system('./genb_test');
^
In file included from /usr/include/c++/4.8/cstdlib:72:0,
from HelloWorld.cpp:4:
/usr/include/stdlib.h:717:12: error: initializing argument 1 of ‘int system(const char*)’ [-fpermissive]
extern int system (const char *__command) __wur;

Answer 1

In c++ ' is used for characters ('a') and " is used for strings ("aaaa").
If you edit system('./genb_test') to be system("./genb_test") it might work.

Answer 2

You have single ' when calling your script. You want double "
#include <cstdlib> /* MODIFIED std::system */
int main()
{
// executing the command("./genb_test")
std::system("./genb_test");
return 0;
}

Answer 3

there is a function named system which could start a shell process to run your script, to do this, you need first include cstdlib header and then call the system function in your code
example
#include <cstdlib>
int main()
{
system("./myscript.sh");
}
The function system need a parameter of type std::string or a C-style string, so you will need the double quotation mark