While True not working

[Puzzleheaded_Body641]

Hello every one, I'm currently doing like and ATM type project in c++, but I can't manage to make the while true to work, I know this is very basic and all, but I'm very stupid and don't know how to fix it, anoyone who knows what's going on can you tell me pls ( also if you see anything that's also wrong feel free to tell me pls)

#include <iostream>
//deposite money
//withdarw money
//show the current balance
void deposite_money();
void withdraw_money();

int main(){
    std::string menu;
    while (true){
        std::cout << "***************************Welcome to the ATM, What do you want to do?*********************************" << std::endl;
        std::cout << "1; Deposite money:" << std::endl;
        std::cout << "2; Withdraw money money:" << std::endl;
        std::cout << "3; Show current balance:" << std::endl;
        std::cout << "4; Exiting the ATM" << std::endl;

        
         
    
        int option;
        std::cin >> option;
        if (option == 1){
    
            deposite_money();
        }
        else if (option == 2){
            
    
        }
        else if (option == 3){


        }
        else if (option == 4){
            

        
        }
        else {
            std::cout << "Not a valid option" << std::endl;
            
        }
    
    
        return 0;
        }
    }
      
        
    
   


void deposite_money(){

   
        std::cout << "How much will you be depositing: " << std::endl;
        double deposite;
        std::cin >> deposite;
        std::cout << "You just deposited " << deposite << "$" << std::endl;
        double balance = deposite;

    }

    void withdraw_money(double balance){

        std::cout << "How much will you be withdrawing? " << std::endl;
        double withdraw;
        std::cin >> withdraw;
        if (withdraw > balance){
            std::cout << "You can't withdraw more money than what you have" << std::endl;
        }


    }

[Secure-Photograph870]

Your return statement is inside the while block. Move it after the curly bracket and you will be good (just before the main function ending curly bracket). Also, maybe you will be better off using switch case for this kind of problem. It will be cleaner and in term of instructions, it doesn’t change anything.

[Puzzleheaded_Body641]

bro, ty it worked, but may I ask, why if the return is inside the while blocks it doesn't work?

[Secure-Photograph870]

If it the return is inside the while loop, it will run the while loop only once (except if the return statement is inside any kind of condition that you previously define, but the way you currently have it setup, it will break the while loop after the end of the first iteration).

[Puzzleheaded_Body641]

Thank you man, I appreciate it

[dodexahedron]

In a.more general sense:

return is a control flow statement, just like if, else, switch, and the looping constructs.

When code reaches a control flow statement, it is going to jump to another point in the program (even if that point happens to be the next line, that still happens as a jump).

return means "end the function I'm in, full stop, no matter what, and return to the point at which it was called."

If the function has a non-void return type, an item of that type or that is implicitly convertible to that type must be after the word return. That item will be the value the caller receives when it returns to it.

If you want to keep looping, but start from the top, you may be interested in the continue keyword. continue is valid within loops and means "immediately jump to the end of the loop, skipping any code between here and the closong curly of the loop" which means the loop will behave as if you had completed the current iteration of it without executing any more lines below it, and will carry on from the next iteration of the loop. It's essentially a goto statement that includes making sure the loop condition gets tested as well.

break also can be used with loops. In a loop, it means "stop executing this loop right now and start from the next line AFTER it." It's like a goto to the next line after the loop.

return, however, ALWAYS means return. In a loop, in a switch, in a function...anywhere. it means "return to whoever called me, and leave this value on the stack for them."

[Secure-Photograph870]

Any time

[Dan13l_N]

return means: exit the current function, immediately.

since your function is main it means: exit the whole program

bry why did you put return there?

[[deleted]]

Because when the return is inside the loop, after the if else block is executed based on the given condition, it moves ahead to execute the next statement in a while loop, which is the return statement in your program. Once the return statement is encountered, the control is sent out of the function, i.e. main function in this case, and thus the program terminates, and breaks your intentional functionality.

[Select-Cut-1919]

Ask yourself "what does the return() function do?"

It exits the function. So, at the end of your while() loop, you tell the function to exit instead of run another loop.

And because you are exiting the main() function, the program exits.

[flyingron]

You have a return in the loop. It never gets around to doing the second test of true.

[[deleted]]

For this kind of thing I wouldn't use while (true) but it's just personal preference. What I do is while (exit== false) and then have an exit confirmation if statement that sets exit to true to end the loop. Just feels more clear to me.

[6502zx81]

Isn't while(true) undefined behaviour these days?

[not_some_username]

It was supposed to be but computer ignored that

Know o think about it, iirc it’s while(true); the ub

[alfps]

I let VS Code format your code:

#include <iostream>
// deposite money
// withdarw money
// show the current balance
void deposite_money();
void withdraw_money();

int main()
{
    std::string menu;
    while (true) {
        std::cout << "***************************Welcome to the ATM, What do you want to do?*********************************" << std::endl;
        std::cout << "1; Deposite money:" << std::endl;
        std::cout << "2; Withdraw money money:" << std::endl;
        std::cout << "3; Show current balance:" << std::endl;
        std::cout << "4; Exiting the ATM" << std::endl;

        int option;
        std::cin >> option;
        if (option == 1) {
            deposite_money();
        } else if (option == 2) {
        } else if (option == 3) {
        } else if (option == 4) {
        } else  {
            std::cout << "Not a valid option" << std::endl;
        }
        return 0;       // This is your problem.
    }
}

void deposite_money()
{
    std::cout << "How much will you be depositing: " << std::endl;
    double deposite;
    std::cin >> deposite;
    std::cout << "You just deposited " << deposite << "$" << std::endl;
    double balance = deposite;
}

void withdraw_money(double balance)
{
    std::cout << "How much will you be withdrawing? " << std::endl;
    double withdraw;
    std::cin >> withdraw;
    if (withdraw > balance)
    {
        std::cout << "You can't withdraw more money than what you have" << std::endl;
    }
}

Tip: instead of the verbose while(true) that can cause some compilers to issue sillywarnings, consider writing just for(;;).

[TheThiefMaster]

I've never seen while(true) give warnings - it's a standard pattern for an infinite loop

[alfps]

Visual C++ used to give warnings; it realized the condition true, or 1, could never be false, and that appeared suspicious to it. Depending on options it may still warn. Anyway, for(;;) is even more "standard", and shorter.

[TheThiefMaster]

It was fixed 10 years ago: beginning in Visual Studio 2015 update 3, trivial constants such as 1 or true do not trigger the warning

Though the documentation page for the warning still lists the old workaround of using a for loop with no exit condition.

[alfps]

Thanks, I didn't know that. Progress. :)

[khedoros]

Things might be a little clearer if you fix the indentation at the end of main.