Thread: decimal ?

  1. #1
    Registered User
    Join Date
    Oct 2003

    decimal ?

    #include <iostream>
    #include <cmath>
    #include <iomanip>
    using namespace std;
    int main()
    	float a, b, c;
    	float x1, x2;
    	float root, temp;
    	cout << "Enter the coefficient of the quadratic function (a*x^2+bx+c): ";
    	cin >> a >> b >> c;
    	temp = (b*b) - (4*a*c);
    		root = sqrt(temp);
    		x1 = (-b+root) / (2.0*a);
    		x2 = (-b-root) / (2.0*a);
    		if (x1==x2)
    			cout << "The single root for the quadratic function -> x = "
    			 << setprecision(2) << x1 << endl;
    			cout << "The root for the quadratic function -> x = "
    			 << setprecision(2) << x1 << " and " << setprecision(2) << x2 << endl;
    		cout << "Invalid input" << endl;
    	return 0;
    when i enter 1 2 1, the output is -1. Why the output is -1 and not -1.00 ?

  2. #2
    Join Date
    Sep 2003
    I believe you need to set the format flags to floating-point, something like this IIRC:
    cout.setf(ios_base::fixed, ios_base::floatfield);
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  3. #3
    Registered User
    Join Date
    Oct 2003
    i declared all my variables as float .... but why it still come out as integer value ? even if i do not use the flag ... it should printf out float value right ? the value stored in each variable should be in decimal format rite ?

  4. #4
    carry on JaWiB's Avatar
    Join Date
    Feb 2003
    Seattle, WA
    setprecision sets how precise it will be, up to 2 decimal places in this case...if both those are zero, then it wont print them out, but if the number was something like 1.2345 it prints out 1.23
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