use c++ to execute a command and get the output of command. It only grab stdout. Use perror or add "2>&1" for grabbing stderr.

exec.cpp

#include <iostream>
#include <cstdarg>
#include <string>
#include <fstream>
#include <memory>
#include <cstdio>

std::string exec(const char* cmd) {
    std::shared_ptr<FILE> pipe(popen(cmd, "r"), pclose);
    if (!pipe) return "ERROR";
    char buffer[128];
    std::string result = "";
    while (!feof(pipe.get())) {
        if (fgets(buffer, 128, pipe.get()) != NULL)
            result += buffer;
    }
    return result;
}


int main(int argc, char const *argv[]) {
    std::string str = exec("brew list");
    std::ofstream output;

    output.open("log.txt");

    if (output.is_open())
        output << str;

    output.close();
    return 0;
}

#include
using namespace std;
int main()
{
int num1, num2, res;
cout<<"Enter Two Numbers: ";
cin>>num1>>num2;
res = num1+num2;
cout<<endl<<"Addition Result = "<<res<<endl;
res = num1-num2;
cout<<endl<<"Subtraction Result = "<<res<<endl;
res = num1*num2;
cout<<endl<<"Multiplication Result = "<<res<<endl;
res = num1/num2;
cout<<endl<<"Division Result = "<<res<<endl;
return 0;
}