Myujth

The else statement in this code does not execute, instead, when a character is entered, it would get stuck in a continuous loop, repeating the lines 33 and 35.

I want to check if the user input is not an integer in the else statement and ask the user again to specify the age.

#include <iostream>
#include <windows.h>
using namespace std;

class User 
 string name;
public:
 string getName()
 return name;
 
 void setName(string newName) 
 name = newName;
 
;

int main()

 /** Initialise Variables */
 string name;
 int age;
 User u1;
 bool running = true;


 while(running) 
 /** Welcome Message w/ User's Name */
 cout << "What is your name?: " << endl;
 cin >> name;
 u1.setName(name);
 cout << "Welcome, " << u1.getName() << "!" << endl;
 returnToAge:
 Sleep(1000);
 cout << u1.getName() << ", to continue, you have to be over 18." << endl;
 Sleep(1000);
 cout << "Please enter your age: " << endl;
 cin >> age;

 if (age >= 18) 
 cout << "You may continue..." << endl;
 Sleep(1000);
 //Enter rest of questionnaire here 


 
 else if(age < 18) 
 cout << "You are underage! Please try again!" << endl;
 Sleep(1500);
 goto returnToAge;
 
 else 
 cout << "INVALID INPUT!" << endl;
 goto returnToAge;
 
 

The problem is that cin >> age will read an integer into age (as that's the only thing age can store), and no matter what integer that is (it's 0 for non-numbers), it will be either bigger or smaller than 18, hence why your else case is never reached.

To detect invalid input, you need to read in a string and then check whether that string represents a valid integer.

You need to check if the input operation succeeded. The easiest way is:

if (cin >> age) 
 // now use age
 else 
 // error

Another way which is equivalent:

cin >> age;
if (!cin) 
 // error

Use std::cin::fail to check wether the user input is an integer.

Secondly, avoid maximum practice using gotos, as it produces Spaghetti code structure. You can replace the goto using a while loop as follows:

while (true) 

 // code
 std::cin >> age;
 if (!std::cin.fail() && age >= 18) // if cin not failed && the codition
 
 /* do something */
 break; // break the loop!
 
 else if (!std::cin.fail() && age < 18) // if cin not failed && the codition
 
 /* do something goto removeed */ 
 
 else std::cout << "INVALID INPUT!" << std::endl; /* goto removeed */