tra2.cpp

来自「這是一個解二為方程式的C++程式語言,對於初學者來說容易理解」· C++ 代码 · 共 36 行

#include <iostream.h>
#include <iomanip.h>
#include <math.h>

int main(void)
{
	cout.setf(ios::fixed,ios::floatfield);
    cout.precision(3);

	double a,b,c;
	double X1,X2;
	double disc;
	double sq;
	cin >>a;
	cout <<"Enter a = " <<a <<"\n"; 
	cin >>b;
    cout <<"Enter b = " <<b <<"\n"; 
	cin >>c;
    cout <<"Enter c = " <<c <<"\n"; 
	disc = b*b-4*a*c;

	if (disc <0.0)
	{
		cerr <<"error" <<"\n";
		return -1;
	}
	
	sq=sqrt(disc);
	X1=(-b+sq)/2*a;
	X2=(-b-sq)/2*a;

	cout <<"The root value x1 =" <<X1 <<"\n";
	cout <<"The root value x2 =" <<X2 <<"\n";
	return 0;
}