not using input after first pass of loop - c++

Question

The intent is to ask a user if they want to play, output options, receive userinput and then simulate a 'roll' the appropriately sided dice. Output the results, and then ask for another choice, etc.
The first cycle of the program works as it should, but instead of it asking if you want to play again it is blank. If you enter a number to select the dice it will output how many sides the first dice had no matter what is chosen.
#include <iostream>
#include <ctime>
using namespace std;
int throwDie(int Sides, int &throwResult)
{
throwResult = 1 + rand() % (Sides - 1 + 1);
return throwResult;
}
int main()
{
int dieTot = 0,
throwNumber = 0,
numberSides = 0,
throwResult = 0;
int die1 = 4;
int die2 = 6;
int die3 = 8;
int die4 = 10;
int die5 = 12;
int die6 = 20;
char rollAgain;
srand(unsigned(time(0) ));
START:
cout << "Do you want Play? ";
cin >> rollAgain;
cout << "How many sides? " << endl;
cout << "1 - 4 sided die\n";
cout << "2 - 6 sided die\n";
cout << "3 - 8 sided die\n";
cout << "4 - 10 sided die\n";
cout << "5 - 12 sided die\n";
cout << "6 - 20 sided die\n";
int choice;
cout << "Enter choice: ";
cin >> choice;
switch( choice ) {
case 1:
do {
cout << "You have choosen a 4 sided die? " << endl;
int numberSides = die1;
cout << numberSides << "-sided die rolled for a value of "
<< throwDie(numberSides, throwResult) << "!" << endl;
dieTot = dieTot + throwResult;
throwNumber++;
cin >> numberSides;
} while (choice != numberSides );
goto START;
break;
case 2:
do {
cout << "You have choosen a 6 sided die? " << endl;
int numberSides = die2;
cout << numberSides << "-sided die rolled for a value of "
<< throwDie(numberSides, throwResult) << "!" << endl;
dieTot = dieTot + throwResult;
throwNumber++;
cin >> numberSides;
cout << endl << "Total for " << throwNumber << " throws = " << dieTot << endl;
} while (choice != numberSides );
break;
case 3:
do {
cout << "You have choosen a 8 sided die? " << endl;
int numberSides = die3;
cout << numberSides << "-sided die rolled for a value of "
<< throwDie(numberSides, throwResult) << "!" << endl;
dieTot = dieTot + throwResult;
throwNumber++;
cin >> numberSides;
cout << endl << "Total for " << throwNumber << " throws = " << dieTot << endl;
} while (choice != numberSides );
break;
case 4:
do {
cout << "You have choosen a 10 sided die? " << endl;
int numberSides = die4;
cout << numberSides << "-sided die rolled for a value of "
<< throwDie(numberSides, throwResult) << "!" << endl;
dieTot = dieTot + throwResult;
throwNumber++;
cin >> numberSides;
cout << endl << "Total for " << throwNumber << " throws = " << dieTot << endl;
} while (choice != numberSides );
break;
case 5:
do {
cout << "You have choosen a 12 sided die? " << endl;
int numberSides = die5;
cout << numberSides << "-sided die rolled for a value of "
<< throwDie(numberSides, throwResult) << "!" << endl;
dieTot = dieTot + throwResult;
throwNumber++;
cin >> numberSides;
cout << endl << "Total for " << throwNumber << " throws = " << dieTot << endl;
} while (choice != numberSides );
break;
case 6:
do {
cout << "You have choosen a 20 sided die? " << endl;
int numberSides = die6;
cout << numberSides << "-sided die rolled for a value of "
<< throwDie(numberSides, throwResult) << "!" << endl;
dieTot = dieTot + throwResult;
throwNumber++;
cin >> numberSides;
cout << endl << "Total for " << throwNumber << " throws = " << dieTot << endl;
} while (choice != numberSides );
break;
default:
cout << "Not a proper entry.\n";
break;
cout << endl << "Total for " << throwNumber << " throws = " << dieTot << endl;
return 0;
}
}
I am assuming the extra code in each of the case statments is:
cout << numberSides << "-sided die rolled for a value of " << throwDie(numberSides, throwResult) << "!" << endl;
dieTot = dieTot + throwResult;
throwNumber++;
cin >> numberSides;
cout << endl << "Total for " << throwNumber << " throws = " << dieTot << endl;
}
while (choice != numberSides );
break;
Would that go at the end of the code? Not in every case statement. Also if I do that would I even need to put the while/do into functions?

Answer 1

This has nothing do with looping.
Try printout out the values obtained from your cin's and you'll see the problem.
You use your goto statement inconsistently, you only return to START in your first case
You don't properly terminate your switch statement
You should just about never use a goto unless you can't do it any other way.
This is horribly written. Why do you need to duplicate everything in each case statement? Seems like you only need to use the switch for setting the value of numberSides and the print out.. The rest should be common... I don't think you need the variables either... see my raw refactor just of your code to simply things...
Refactoring your code makes it much more readable: see below
#include <iostream>
#include <ctime>
using namespace std;
//This function will throw a dice returning the result while updating the parameter.
int throwDie(int Sides, int &throwResult)
{
throwResult = 1 + rand() % (Sides); //Sides - 1 + 1 == Sides
return throwResult;
}
//Display the menu
void displayMenu()
{
cout << "How many sides? \n"
<< "1 - 4 sided die\n"
<< "2 - 6 sided die\n"
<< "3 - 8 sided die\n"
<< "4 - 10 sided die\n"
<< "5 - 12 sided die\n"
<< "6 - 20 sided die\n"
<< "CTRL-D to quit";
}
int main()
{
int dieTot = 0,
throwNumber = 0,
numberSides = 0,
throwResult = 0;
// THESE ARENT NEEDED
// sides = 4+2*(X-1)
//int die1 = 4;
//int die2 = 6;
//int die3 = 8;
//int die4 = 10;
//int die5 = 12;
//int die6 = 20;
srand(unsigned(time(0) ));
displayMenu();
int choice;
while ( cin >> choice ) {
/* cin >> choice will return 0 / fail if they enter CTRL-D or enter
something other than a number... you'll have to handle that in another way */
if ( choice < 1 || choice > 6 ) {
cout << "Invalid choice try again!";
continue;
}
//numberSides = 4+2*(choice-1); //fast way
switch (choice) {
case 6:
numberSides = 20;
break;
case 1:
//if you dont want to do this slick trick of fall through
//numberSides = 4;
//break;
case 2:
case 3:
case 4:
case 5:
numberSides = 4+2*(choice-1); // use this for 1,2,3,4,5;
break;
}
cout << "You have chosen a " << numberSides << " sided die.\n"
<< numberSides << "-sided die rolled for a value of "
<< throwDie(numberSides, throwResult) << "!" << endl;
dieTot += throwResult;
throwNumber++;
}
cout << "\n\n" << "Total for " << throwNumber << " throws = " << dieTot << endl;
return 0;
}