📅  最后修改于: 2020-09-25 06:30:42             🧑  作者: Mango
对于二次方程ax 2 + bx + c = 0 (其中a,b和c为系数),其根由以下公式给出。
术语b 2 -4ac
被称为二次方程的判别式。判别式说明了根的性质。
#include
#include
using namespace std;
int main() {
float a, b, c, x1, x2, discriminant, realPart, imaginaryPart;
cout << "Enter coefficients a, b and c: ";
cin >> a >> b >> c;
discriminant = b*b - 4*a*c;
if (discriminant > 0) {
x1 = (-b + sqrt(discriminant)) / (2*a);
x2 = (-b - sqrt(discriminant)) / (2*a);
cout << "Roots are real and different." << endl;
cout << "x1 = " << x1 << endl;
cout << "x2 = " << x2 << endl;
}
else if (discriminant == 0) {
cout << "Roots are real and same." << endl;
x1 = (-b + sqrt(discriminant)) / (2*a);
cout << "x1 = x2 =" << x1 << endl;
}
else {
realPart = -b/(2*a);
imaginaryPart =sqrt(-discriminant)/(2*a);
cout << "Roots are complex and different." << endl;
cout << "x1 = " << realPart << "+" << imaginaryPart << "i" << endl;
cout << "x2 = " << realPart << "-" << imaginaryPart << "i" << endl;
}
return 0;
}
输出
Enter coefficients a, b and c: 4
5
1
Roots are real and different.
x1 = -0.25
x2 = -1
在此程序中, sqrt()
库函数用于查找数字的平方根。