how main() is call from main()

[salman amin]

I got confused in a topic that is how main() is called from main()
I know its due to recursion bt how ?

please allustrate ur ansr with an example

Regards

[Disch]

You shouldn't call main from anywhere.

[blackcoder41]

You shouldn't call main from anywhere.

that is indeed correct

or maybe there is another main() function in your code

post the code you have read to clear this.

[jsmith]

In C++ it is illegal to call main() explicitly.

[freeze]

me too, can someone teach me how to do it,, or just give me a simple example,so that a beginner like me will understand it most..help me experts plss..im new to c++

[olredixsis]

so you mean this code is incorrect?

void userInput(char* checkInput);

int main()
{
	bool correctInput = false;
	char input[80];
	userInput(input);
	correctInput = braceCheck(input);
	if(correctInput == true){
		cout<<"CORRECT!"<<endl;
		main();
	}
	else{
		cout<<"INCORRECT!"<<endl;
		main();
	}

}//end main
void userInput(char* checkInput)
{
	cout<<"Input Anything: ";
	cin>>checkInput;
	if((checkInput[0]=='e')&&(checkInput[1]=='x')&&(checkInput[2]=='i')&&(checkInput[3]=='t')){
		exit (0); //terminates the program
	}//end if
}//end userInput function

//........ 

-----------------------
but what will I do if I want the code to return to userInput() function again?
If I use userInput(input) instead of main() it will only recurse 1 time.
so what is the best solution for this? thx

[gcampton]

why not just say...

void userInput(char* checkInput);
void runApp();

int main()
{
    runApp();
    return 0;

}//end main
void userInput(char* checkInput)
{
	cout<<"Input Anything: ";
	cin>>checkInput;
	if((checkInput[0]=='e')&&(checkInput[1]=='x')&&(checkInput[2]=='i')&&(checkInput[3]=='t')){
		exit (0); //terminates the program
	}//end if
}//end userInput function

void runApp()
{
        bool correctInput = false;
	char input[80];
	userInput(input);
	correctInput = braceCheck(input);
	if(correctInput == true){
		cout<<"CORRECT!"<<endl;
		runApp();
	}
	else{
		cout<<"INCORRECT!"<<endl;
		runApp();
	}
}

[Disch]

Both of those code examples are awful

1) Repeatedly calling a function sucks up stack space. Just use a loop.

2) Exiting with exit() is ill advised, IMO. It's best to exit by returning normally from main.

3) Why are newbies so afraid of std::string? char arrays are a lot meaner.

string userInput();

int main()
{
	string input;

	while(true)  // loop indefinitely
	{
		input = userInput();
		if(input == "exit")  // if the user typed "exit"
			break;    // break out of the infinite loop

		// otherwise do the rest:
		if( braceCheck(input) )
			cout << "CORRECT!" << endl;
		else
			cout << "INCORRECT!" << endl;
	}

	return 0;
}//end main

string userInput()
{
	string input;
	cout<<"Input Anything: ";
	cin>>input;

	return input;
}//end userInput function 

[blackcoder41]

disch wrote:

Both of those code examples are awful

hahaha lmao

disch wrote:

Why are newbies so afraid of std::string? char arrays are a lot meaner.

yeah i also notice that, maybe because of how most tutorials do.

[Duthomhas]

Explicitly calling main() is always a BAD IDEA.

You just don't know what will happen (since K&R just assumed that no one in their right mind would ever recurse on main). Hence, the C++ standards committee decided to address the issue and expressly forbid it.

Just say "no" to return main();!

[olredixsis]

ok thanks for the idea.
It helps me a lot.
I will now use string instead of char arrays.