最直观的方法

解题思路:

注意事项:

参考代码:

#include <stdio.h>

#include <math.h>

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

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

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

int main() {

    double a,b,c;

    scanf("%lf%lf%lf",&a,&b,&c);

    double delta=b*b-4*a*c;

    if(delta>0)

    {

        big(a,b,c);

    }

    else if(delta==0)

    {

        equal(a,b,c);

    }

    else

    {

        small(a,b,c);

    }

    return 0;

}

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

{

    double delta=b*b-4*a*c;

    double x1=(-b+sqrt(delta))/(2*a);

    double x2=(-b-sqrt(delta))/(2*a);

    printf("x1=%.3lf x2=%.3lf",x1,x2);

}

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

{

    double x1=(-b)/(2*a);

    double x2=(-b)/(2*a);

    printf("x1=%.3lf x2=%.3lf",x1,x2);

}

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

{

    double real=(-b)/(2*a);

    double imag=sqrt(-(b*b-4*a*c))/(2*a);

    printf("x1=%.3lf+%.3lfi x2=%.3lf-%.3lfi",real,imag,real,imag);

}