[SOLVED] CS c++ // inspired from: https://docs.microsoft.com/en-us/cpp/cpp/program-termination?view=vs-2019

// inspired from: https://docs.microsoft.com/en-us/cpp/cpp/program-termination?view=vs-2019
// abort.cpp
#include
#include

class ShowData {
public:
// Constructor opens a file.
// This constructor is called when the sd1 and sd2 objects are created below
// and instantiated with strings, essentially acting as a convertor between the
// char* type and the ShowData type.
ShowData(const char* szDev) {
// fopen_s() uses an error code
errno_t err;
// creates a file open in write mode and assigns it to the OutputDev data member
err = fopen_s(&OutputDev, szDev, w);
}

// Destructor closes the file.
// If the destructor is not calledsuch as if abort() is calledthe file handled is not freed.
~ShowData() {
// prints a string to the device, indicating that the destructor was called.
fputs(closing output device, OutputDev);
// close the device
fclose(OutputDev);
}

// Disp function writes a string on the output device.
void Disp(const char* szData) {
fputs(szData, OutputDev);
}
private:
FILE* OutputDev;
};

//Define a static object of type ShowData. The output device
// selected is CON the standard output device.
//CON is a Windows C++ reserved name which stants for the console output, which is written to as a file.
ShowData sd1 = CON;

int main() {
//Define an object of type ShowData local to the main functions body. The output
// is directed to a file called hello.dat
ShowData sd2 = hello.dat;

sd1.Disp(hello to default device
);
sd2.Disp(hello to file hello.dat
);
// if return(0) is used, the main function must return int, not void.
// This triggers the destructors before the program is terminated.
// See the message output in the console and the file.
// return(0); // uncomment this line to try

// if exit(0) is used, the main function can return void or int.
// This triggers the destructors before the program is terminated.
// See the message output in the console and the file.
// exit(0); // uncomment this line to try

// if abort() is used, the main function can return void or int,
// and the global objects and the objects declared in the main function
// are not freed, as their destructor is not called.
// See the absence of message output in the console and the file.
// abort(); // uncomment this line to try

// if none of the above is executed before the end of the main function
// (i.e. return, ext, abort), the program terminates at
// then end of the main functions body, and the destructors are called for all
// global objects and objects declared locally in the main functions body.
// See the message output in the console and the file.
}