Legal drinking age

[jacobluke]

My program is crashing when I type in the the character that registers for the else condition. The if, and the else if work perfectly fine. Any ideas?
Appreciate the help.



// LEGAL DRINKING AGE

#include <iostream>
using namespace std;

int main()
{
int age;
bool answer;
answer = true;

while (answer == true)
{
cout << "Please enter your age: ";
cin >> age;

if ((age >= 21) && (age <= 125))
{
cout << "You can drink.\n";
}
else if ((age > 0) && (age < 21))
{
cout << "You cannot drink.\n";
}
else
{
cout << "Are you sure you're human?";
}

cout << "Would you like to try again? (tpye 1 for yes, and 0 for no)";
cin >> answer;
}
return 0;
}

[wildblue]

What are you entering to trigger the else condition?

[Thomas1965]

Your code looks fine and works well when you enter a number. Of course it crashes when you input any other characters than digits for age or any other key than 0 or 1 for answer.
One way to solve it is to get the input as a string, check that it is valid and convert it to an int or bool.

[jacobluke]

The idea is; if the input is anything outside the (decision makers) boundaries for the if and else if, which would be anything that is not the integers 1-125, that it would output the else: "Are you human?".

For instance, if I type in 'a' for the input. I get that crash i mentioned, instead of the else statement.

[jacobluke]

Oh.. It's crashing because mixed data types. Obvious oversight on my part. Thanks Thomas I see what you mean. Is there any reason to convert it though?

[shadder]

You may use cin.fail() and cin.ignore().

[cire]

Is there any reason to convert it though?

One reason might be to make it work. Telling if a string represents a number that is above and below a particular value isn't a particularly convenient thing to do without converting the string into an integer value.

Here's a version using a string and conversion (and execeptions, since std::stoi may throw one.)

#include <iostream>
#include <string>

int to_int(const std::string& txt, int base = 10) {    
    std::size_t consumed;
    int value = std::stoi(txt, &consumed, base);
        
    if (consumed != txt.size()) 
        throw std::invalid_argument("Full text not convertible to integer value");

    return value;
}

int main()
{
    bool should_continue;
    do 
    {
        std::string input;

        std::cout << "Please enter your age: ";
        std::cin >> input;

        try {
            int age = to_int(input);
            if (age < 0 || age >= 125)
                throw "You ain't human";

            if (age >= 21)
                std::cout << "You can drink.\n";
            else
                std::cout << "You cannot drink.\n";
        }
        catch (...) { std::cout << "Are you sure you're human?\n"; }


        std::cout << "Would you like to try again? (1 = yes)\n> ";
        std::cin >> input;

        should_continue = input == "1";

    } while (should_continue);
}