I have been able to write a program to solve the quadratic equation for input like:

a=10 b=100 c=200 and a=1 b=2 c=5

but for input like a=1.29 b=3.5 and c=4.6 I get innaccurate solutions.

for example instead of -1.36 + 1.31i I output -2.2575000000000003 + 2.1859696132380244i to the console

here's what I'm using right now:

double discriminant = ((Math.pow(b, 2)) -(4 * a * c));

 if (discriminant < 0) {
            discriminant *= -1;
            secondSolnString = "" + " " + (-1*b / 2 * a) + " - "
                    + (Math.sqrt(discriminant) / 2 * a) + 'i';

}

any suggestions or hints are welcome!

mhajianpour wrote:

Chris,
Remember the order of precendence when you're doing calculations in any language. Multiplication and division are both executed at the same level and are executed from left to right if not paranthesized. Check that in your code.

--
Mahan H.

Thanks! I made the correction and it works now. I can't believe I didn't catch that earlier.

    Scanner keyboard = new Scanner(System.in);

        input = keyboard.nextInt();
       
        int power = 0;
        int base = 2;
       
        if(base == 2){
            base = (int) Math.pow(2,power++);

            for(int i = input % 2; i > 0; i++ ){
               
                input *= base;
           
                System.out.println( "The binary representation is:\t" + input);

            }
        }

 

Any suggestions...

You definitely want to recheck the flow of this program. Lets say a person types "11" into the console. After that the program checks that the value of base is 2 and assigns the value 1 to base(because you initialized power to 0) and then increments power(power++ is the postincrement operator). Then it assigns the value (%input) to i. If the variable i is an even number the loop never executes if the variable is odd it executes forever.

here is some pseudocode that may be of use to to:
read input from keyboard as a string (use the nextLine() method of the scanner class)
iterate through the string
at each index raise the base to the appropriate power and add that value to an integer variable
print the integer variable
hope that helps!

Ya I am not sure if I am doing it right.

I can get it to reprint the input String using the for loop. But I am not sure if anything is suppose to go inside the for loop block of code. On paper it makes sense, but coding is different...

I am to suppose to parse the String into a integer right?Because thats what I did and tried putting it into a loop.