C++ Simple Math Program

[blueflamez13]

Hi guys!

Making a simple math program calculating the quadratic formula so that I can get practice using multiple methods and basic in/out prompts. I wanted to add a simple check to make sure that what is being inputed for "a", "b", or "c" isn't a character that cannot be used in a calculation. Not sure about how to work the exception for it. Any advice? This is what I have so far..

[code] #include <iostream>
#include <math.h>
#include <stdio.h>
#include <cmath>
#include <string>


using namespace std;

//Discriminate Method :: Formula (b^2 - 4ac)

float discriminate(float a, float b, float c)
{
float discrim;

try
{
discrim = (b*b) - (4 * a * c);

}

catch(exception& e)
{
cout << "error" << endl;

}
return discrim;

}


float quadratic(float a, float b, float c)
{
float discrim = discriminate(a,b,c);

if (discrim < 0)
{
cout << "Discriminate is imaginary" << endl;
return 0;
}

else
{
float quad = sqrt(discrim);
return quad;
}

} //End of Quadratic Method



int main()
{

//Variable Declaration
float a, b, c;

//Welcome Message
cout << "Welcome to Josh's Quadratic Formula C++ Program" << endl;
cout << "================================================" << endl;
cout << "" << endl;


cout << "Input A: " << endl;
cin >> a;


cout << "Input B: " << endl;
cin >> b;


cout << "Input C: " << endl;
cin >> c;


float answer = quadratic(a,b,c);


if (answer == 0)
{
cout << "Imaginary Number: Cannot Calculate" << endl;
}

else
{
cout << "The answer: +/- " << answer << endl;
}
return 0;


}
[code]

[D_Drmmr]

See http://www.parashift.com/c++-faq-lit....html#faq-15.2 for full explanation.
If something that is not a float is entered for a, then b and c will not actually be read. Depending on how you want to handle it, you could check after each input or after several inputs.

PS closing code tag is [/code], not [code].

[blueflamez13]

haha oops on the [\code] ;p That's what I meant to put!

Thanks for that article! Filled with great information. I will be sure to give those things a try when I get the chance later today!

[DavidB]

Don't forget the -b plus or minus, and the (2a):

quad = (-b +/- sqrt(discrim))/(2a);