How do I pass a variable through Python using C++ in Python.h

Question

I wanted to try out embedding Python into C++. I was able to get that to work but I wanted to start writing prints with variables which are in declared in c++. For example:

(C++)

int num = 43;
PyRun_SimpleString("print("+num+")");

char g;
std::cin>>g;
PyRun_SimpleString("print("+g+")");

I tried to figure out how to use other related functions, but I don't seen to find enough information.

Answer 1

To pass char,

Python script:

def test(person):
    return "Hello " + person;

C++:

PyObject *pName, *pModule, *pFunc, *pArgs, *pValue;
pName = PyUnicode_FromString((char*)"script");
pModule = PyImport_Import(pName);
pFunc = PyObject_GetAttrString(pModule, (char*)"test");
pArgs = PyTuple_Pack(1, PyUnicode_FromString((char*)"User"));
pValue = PyObject_CallObject(pFunc, pArgs);
auto result = _PyUnicode_AsString(pValue);
std::cout << result << std::endl;

Output:

Hello User

To pass integer it's the same like above. Here you are passing over double 2.0.

pArgs = PyTuple_Pack(1,PyFloat_FromDouble(2.0));
pValue = PyObject_CallObject(pFunc, pArgs);

You can refer to all the apis here >> https://docs.python.org/3/c-api/