Input test

[gatorguy22]

Hello everyone,
I'm very new to programming and taking an intro course for fun. I have a project due tonight that I wanted to spice up a bit if I can. Here is my code:

//This program is designed to output which substances will either freeze or boil
//given a user generated temperature.

#include <iostream>

using namespace std;

int main()
{
//Temperature variable input from user.
int temp;

//Display of programs purpose.
cout << "Welcome to the Freeze & Boil Program!\n";
cout << "This program will take any temperature you type in\n";
cout << "and display what substances on record will freeze or boil\n";
cout << "at that point.\n" << endl;

//Program prompts user to input a temperature to be tested.
cout << "Please enter a temperature in degrees Farenheit:\n";
cin >> temp;

//Program processes given temperature so it may output each corresponding substance.
if
cout << "That is not a valid temperature. Please try again.\n";

cout << endl << "Subsances that will freeze:\n";
if (temp <= -173)
cout << "Ethyl Alcohol\n";

if (temp <= -38)
cout << "Mercury\n";

if (temp <= -362)
cout << "Oxygen\n";

if (temp <= 32)
cout << "Water\n";

cout << endl << "Substances that will boil:\n";
if (temp >= 172)
cout << "Ethyl Alcohol\n";

if (temp >= 676)
cout << "Mercury\n";

if (temp >= -306)\
cout << "Oxygen\n";

if (temp >= 212)
cout << "Water\n";

cout << endl << "Thank you for using the Freeze & Boil Program!" << endl;

cin.get();

return 0;
}

I know it's a very simple and common program. So far The program works correctly (at least with the tests I've attempted) but I wanted to add to it the ability to catch any input that isn't a number. Such as a-z or A-Z. You can see I've started the If function with a complementing cout statement.

Keeping in mind I'm still a novice is there an easy way for me to code in what I need. I know it's possible but I'm trying to stay close to the beginner level.

[firedraco]

First, please use code tags when posting code:
http://www.cplusplus.com/articles/z13hAqkS/

You'll want to check to see if cin is in an error state:

if(std::cin>>temp) {
    //we got a value
} else {
    //there was a problem...do something
    //don't forget to clear the stream of the bad data!
    std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
    std::cin.clear();
}

[newbiee999]

I replaced line 24 with cin.fail(), so if user enters a non-integer then it will display "The temp is invalid".
Then I put everything else in the else { } brackets, so they get compiled only if the temperature is valid.

//This program is designed to output which substances will either freeze or boil
//given a user generated temperature.

#include <iostream>

using namespace std;

int main()
{
//Temperature variable input from user.
int temp;	

//Display of programs purpose.
cout << "Welcome to the Freeze & Boil Program!\n";
cout << "This program will take any temperature you type in\n";
cout << "and display what substances on record will freeze or boil\n";
cout << "at that point.\n" << endl;

//Program prompts user to input a temperature to be tested.
cout << "Please enter a temperature in degrees Farenheit:\n";	
cin >> temp;

//Program processes given temperature so it may output each corresponding substance.
if (cin.fail())
cout << "That is not a valid temperature. Please try again.\n";

else{
cout << endl << "Subsances that will freeze:\n";
if (temp <= -173)
cout << "Ethyl Alcohol\n";

if (temp <= -38)
cout << "Mercury\n";

if (temp <= -362)
cout << "Oxygen\n";

if (temp <= 32)
cout << "Water\n";

cout << endl << "Substances that will boil:\n";
if (temp >= 172)
cout << "Ethyl Alcohol\n";

if (temp >= 676)
cout << "Mercury\n";

if (temp >= -306)\
cout << "Oxygen\n";

if (temp >= 212)
cout << "Water\n";

cout << endl << "Thank you for using the Freeze & Boil Program!" << endl;

cin.get();
}
return 0;
}

Hope that helps!

[andywestken]

Dupe post!!!

Here...

And there...

Input test
http://www.cplusplus.com/forum/beginner/166565/

Andy