C语言程序设计教程（第三版）课后习题8.2 （C++代码）

解题思路:





注意事项:





参考代码:

#include <iostream>

#include <iomanip>

#include <cmath>

using namespace std;

int main()

{

void n1(double a,double b,double c);

void n2(double a,double b,double c);

double a,b,c;

cin>>a>>b>>c;

if(b*b-4*a*c>=0) n1(a,b,c);

else if(b*b-4*a*c<0) n2(a,b,c);

return 0;

}

void n1(double a,double b,double c)

{

cout<<"x1="<<setprecision(3)<<setiosflags(ios::fixed)<<-b/(2*a)<<'+'<<sqrt(b*b-4*a*c)/(2*a)<<'i'<<' ';

cout<<"x2="<<setprecision(3)<<setiosflags(ios::fixed)<<-b/(2*a)<<'-'<<sqrt(b*b-4*a*c)/(2*a)<<'i'<<endl;

}

void n2(double a,double b,double c)

{

cout<<"x1="<<setprecision(3)<<setiosflags(ios::fixed)<<-b/(2*a)<<'+'<<sqrt(-1*(b*b-4*a*c))/(2*a)<<'i'<<' ';

cout<<"x2="<<setprecision(3)<<setiosflags(ios::fixed)<<-b/(2*a)<<'-'<<sqrt(-1*(b*b-4*a*c))/(2*a)<<'i'<<endl;

}