If/else loops: C++ Program: Won't display final prompt/final loop - c++

Question

I'm having a lot of trouble with this assignment for my first C++ course.
I have figured out how to get it to properly ask the user what operation they would like to use (add, subtract, multiply), generate random numbers between 0-9, and how to ask the user to solve the problem and respond if it is correct or incorrect.
After this point, the program is supposed to ask the user if they would like to continue (by pressing y) or quit (by pressing Q), with an error message for the user when they enter any other letter, but for some reason this part doesn't display when running the program.
How do I get the loop to work correctly, allowing me to do the final prompt, and THEN repeat the whole program only when pressing Y or quit when pressing Q?
Note: I'm VERY new to coding in general, and this is my very first C++ course, so I do not know yet how to make this code more succinct:
#include <iostream>
#include <cstdio>
#include <time.h>
#include <stdlib.h>
using namespace std;
int main()
{
while (true)
{
// Generate two random single-digit integers btwn 0-9
srand(time(0));
int num1 = rand() % 10;
int num2 = rand() % 10;
int operation, play, num3, guess, Y, Q;
// If num1 < num2, swap num1 with num2
if (num1 < num2)
{
int temp = num1;
num1 = num2;
num2 = temp;
}
cout << "Choose an operation." << endl;
cout << "Enter 1 to add, 2 to subtract, or 3 to multiply: " << endl;
cin >> operation;
if (operation > 3 || operation < 1)
{
cout << "Your operation choice isn't valid! Please try again, using 1, 2, or 3." << endl;
cout << "Choose an operation." << endl;
cout << "Enter 1 to add, 2 to subtract, or 3 to multiply: " << endl;
cin >> operation;
}
else if (operation == 1)
{
cout << "You chose addition." << endl;
num3 = num1 + num2;
cout << "What is " << num1 << " + " << num2 << " ?: " << endl;
cin >> guess;
if (guess != num3)
{
cout << "That is incorrect. Please try again." << endl;
cout << "" << endl;
cout << "What is " << num1 << " + " << num2 << " ?: " << endl;
cin >> guess;
}
else if (guess == num3)
{
cout << "That is correct!" << endl;
cout << "" << endl;
}
}
else if (operation == 2)
{
cout << "You chose subtraction." << endl;
num3 = num1 + num2;
cout << "What is " << num1 << " - " << num2 << " ?: " << endl;
cin >> guess;
if (guess != num3)
{
cout << "That is incorrect. Please try again." << endl;
cout << "" << endl;
cout << "What is " << num1 << " - " << num2 << " ?: " << endl;
cin >> guess;
}
else if (guess == num3)
{
cout << "That is correct!" << endl;
cout << "" << endl;
}
}
else if (operation == 3)
{
cout << "You chose multiplication." << endl;
num3 = num1 * num2;
cout << "What is " << num1 << " * " << num2 << " ?: " << endl;
cin >> guess;
if (guess != num3)
{
cout << "That is incorrect. Please try again." << endl;
cout << "" << endl;
cout << "What is " << num1 << " * " << num2 << " ?: " << endl;
cin >> guess;
}
else if (guess == num3)
{
cout << "That is correct!" << endl;
cout << "" << endl;
}
}
while (guess != num3)
{
int play, Y, Q;
cout << "Would you like to play again? Press Y for yes or Q for
quit" << endl;
cin >> play;
if (play != Y || play != Q)
{
cout << "That is not a valid choice. Please choose Y for yes
or Q to quit. " << endl;
cin >> play;
}
else
{
if (play == Y)
{
cout << "Thank you for playing! Let's play again!" << endl;
cout << "" << endl;
}
else if (play == Q)
{
cout << "Thank you for playing! See you next time!" << endl;
cout << "" << endl;
}
break;
}
}
}
return 0;
}

Answer 1

There are few things here...
1. Only seed once
Move srand(time(0)); out of the while loop and to the top of main. If you repeatedly seed in the same second (if time(0) doesn't change), you'll get the same "random" numbers twice.
2. What happens to num3 if they don't enter a valid operation?
You never initalize num3, so if they don't choose a valid operation, num3 will have a junk value. You then go on to run a loop whose condition depends on num3's value! (while (guess != num3))
3. else { ... if { is the same as else if {
In your final loop, bring the if (play == Y) and else if (play == Q) out of that nested if and make them else if's.
4. Your last loop condition is incorrect
Is while (guess != num3) really right? You want to loop until they enter valid input, so why are you looping while guess != num3?

Answer 2

The problem is found with in the second while-loop. The play variable should be declared as a char rather than an int. Plus you don't need to compare it with Y and Q integer variables. Here is a solution. I hop it will help you:
#include <iostream>
#include <cstdio>
#include <time.h>
#include <stdlib.h>
using namespace std;
int main()
{
bool loop = true;
while (loop)
{
// Generate two random single-digit integers btwn 0-9
srand(time(0));
int num1 = rand() % 10;
int num2 = rand() % 10;
int operation, play, num3, guess, Y, Q;
// If num1 < num2, swap num1 with num2
if (num1 < num2)
{
int temp = num1;
num1 = num2;
num2 = temp;
}
cout << "Choose an operation.\n\t-----------------------" << endl;
cout << "\tEnter 1 to add,\n\tEnter 2 to subtract, or\n\tEnter 3 to multiply\n\t-----------------------\n\t\tEnter: ";
cin >> operation;
if (operation > 3 || operation < 1)
{
cout << "Invalid choice! Please try again." << endl;
continue;
}
else if (operation == 1)
{
cout << "You chose addition." << endl;
num3 = num1 + num2;
cout << "What is " << num1 << " + " << num2 << " = ";
cin >> guess;
if (guess != num3)
{
cout << "That is incorrect. Please try again." << endl;
cout << "What is " << num1 << " + " << num2 << " = ";
cin >> guess;
}
else if (guess == num3)
cout << "That is correct!" << endl;
}
else if (operation == 2)
{
cout << "You chose subtraction." << endl;
num3 = num1 + num2;
cout << "What is " << num1 << " - " << num2 << " = ";
cin >> guess;
if (guess != num3)
{
cout << "That is incorrect. Please try again." << endl;
cout << "What is " << num1 << " - " << num2 << " = ";
cin >> guess;
}
else if (guess == num3)
cout << "That is correct!" << endl;
}
else if (operation == 3)
{
cout << "You chose multiplication." << endl;
num3 = num1 * num2;
cout << "What is " << num1 << " * " << num2 << " = ";
cin >> guess;
if (guess != num3)
{
cout << "That is incorrect. Please try again." << endl;
cout << "What is " << num1 << " * " << num2 << " = ";
cin >> guess;
}
else if (guess == num3)
cout << "That is correct!" << endl;
}
while (true)
{
char play;
cout << "Would you like to play again? Press Y for yes or Q for quit: ";
cin >> play;
if (play == 'Y' || play == 'y')
break;
else if(play == 'Q' || play == 'q')
{
loop = false;
cout << "Good bye.\n";
break;
}
else
cout<< "Invalid choice.\n";
}
}
return 0;
}
Making the menu a little interactive is also good, peace.

Answer 3

It's could be better to use a switch case to select the correct operation like this:
Switch(operation) {case 1: break;}
You need to add one more while too
SO the correct code should be like this:
#include <iostream>
#include <cstdio>
#include <time.h>
#include <stdlib.h>
using namespace std;
int main()
{
int operation, num3, guess,num1,num2,temp;
srand(time(0));
char play;
do
{
// Generate two random single-digit integers btwn 0-9
num1 = rand() % 10;
num2 = rand() % 10;
// If num1 < num2, swap num1 with num2
if (num1 < num2)
{
temp = num1;
num1 = num2;
num2 = temp;
}
do
{
cout << "Choose an operation." << endl;
cout << "Enter 1 to add, 2 to subtract, or 3 to multiply: " << endl;
cin >> operation;
if (operation > 3 || operation < 1)
{
cout << "Your operation choice isn't valid! Please try again, using 1, 2, or 3." << endl;
cout << "Choose an operation." << endl;
cout << "Enter 1 to add, 2 to subtract, or 3 to multiply: " << endl;
cin >> operation;
}
}while(operation>3 || operation<1);
switch(operation)
{
case 1:
cout << "You chose addition." << endl;
num3 = num1 + num2;
do
{
cout << "What is " << num1 << " + " << num2 << " ?: " << endl;
cin >> guess;
if (guess != num3)
{
cout << "That is incorrect. Please try again." << endl;
cout << "" << endl;
}
}while(guess!=num3);
cout << "That is correct!" << endl;
cout << "" << endl;
break;
case 2:
cout << "You chose subtraction." << endl;
num3 = num1 - num2;
do
{
cout << "What is " << num1 << " - " << num2 << " ?: " << endl;
cin >> guess;
if (guess != num3)
{
cout << "That is incorrect. Please try again." << endl;
cout << "" << endl;
}
}while(guess!=num3);
cout << "That is correct!" << endl;
cout << "" << endl;
break;
case 3:
cout << "You chose multiplication." << endl;
num3 = num1 * num2;
do
{
cout << "What is " << num1 << " * " << num2 << " ?: " << endl;
cin >> guess;
if (guess != num3)
{
cout << "That is incorrect. Please try again." << endl;
cout << "" << endl;
}
}while(guess!=num3);
cout << "That is correct!" << endl;
cout << "" << endl;
break;
}
do
{
cout << "Would you like to play again? Press Y for yes or Q for quit" << endl;
cin >> play;
if (play != 'Y' && play != 'Q')
{
cout << "That is not a valid choice. Please choose Y for yes or Q to quit. " << endl;
}
}while(play!='Y' && play!='Q');
if (play == 'Y')
{
cout << "Thank you for playing! Let's play again!" << endl;
cout << "" << endl;
}
else
{
cout << "Thank you for playing! See you next time!" << endl;
cout << "" << endl;
}
}while(play=='Y');
return 0;
}

Answer 4

Solution:
P29: Practice Arithmetic Skills (if/else , loop)
Description:
"Write a program to let a child practice arithmetic skills.
The program should first ask for what kind of practice is wanted: +, -, * , and let the user repeat the practice as many times as desired, until "Q" is entered.
Two random numbers will be generated from (0 - 9).
If the child answers the equation correctly, a message should appear , and they can then go to the next problem(two different numbers generated).
If the child answers incorrectly, a message should appear & the problem should be repeated (same numbers used)."
Finally fixed!:
#include <iostream>
#include <cstdio>
#include <time.h>
#include <stdlib.h>
using namespace std;
int main()
{
int operation, num3, guess, num1, num2, temp;
char play;
srand(time(0));
do
{
num1 = rand() % 10;
num2 = rand() % 10;
if (num1 < num2)
{
temp = num1;
num1 = num2;
num2 = temp;
}
do
{
cout << "Choose an operation." << endl;
cout << "Enter 1 to add, 2 to subtract, or 3 to multiply: " << endl;
cout << "" << endl;
cin >> operation;
if (operation > 3 || operation < 1)
{
cout << "Your operation choice isn't valid! Please try again, using 1, 2, or 3." << endl;
}
}while (operation > 3 || operation < 1);
switch(operation)
{
case 1:
cout << "You chose addition." << endl;
num3 = num1 + num2;
cout << "" << endl;
do
{
cout << "What is " << num1 << " + " << num2 << " ?: " << endl;
cout << "" << endl;
cin >> guess;
cout << "" << endl;
if (guess != num3)
{
cout << "That is incorrect. Please try again." << endl;
cout << "" << endl;
}
} while (guess != num3);
if (guess == num3)
{
cout << "That is correct!" << endl;
cout << "" << endl;
}
break;
case 2:
cout << "You chose subtraction." << endl;
num3 = num1 - num2;
cout << "" << endl;
do
{
cout << "What is " << num1 << " - " << num2 << " ?: " << endl;
cout << "" << endl;
cin >> guess;
cout << "" << endl;
if (guess != num3)
{
cout << "That is incorrect. Please try again." << endl;
cout << "" << endl;
}
} while (guess != num3);
if (guess == num3)
{
cout << "That is correct!" << endl;
cout << "" << endl;
}
break;
case 3:
cout << "You chose multiplication." << endl;
num3 = num1 * num2;
cout << "" << endl;
do
{
cout << "What is " << num1 << " * " << num2 << " ?: " << endl;
cout << "" << endl;
cin >> guess;
cout << "" << endl;
if (guess != num3)
{
cout << "That is incorrect. Please try again." << endl;
cout << "" << endl;
}
} while (guess != num3);
if (guess == num3)
{
cout << "That is correct!" << endl;
cout << "" << endl;
}
break;
}
do
{
cout << "Would you like to play again? Press Y for yes or Q for quit" << endl;
cout << "" << endl;
cin >> play;
if (play != 'Y' && play != 'Q')
{
cout << "That is not a valid choice. Please choose Y for yes or Q to quit. " << endl;
cout << "" << endl;
}
}
while(play !='Y' && play !='Q');
if (play == 'Y')
{
cout << "Thank you for playing! Let's play again!" << endl;
cout << "" << endl;
}
else
{
cout << "Thank you for playing! See you next time!" << endl;
cout << "" << endl;
}
}
while(play=='Y');
return 0;
}