[编程入门]自定义函数求一元二次方程-题解（C语言代码）

解题思路:参考大佬的，费劲了千辛万苦总算写出来了

注意事项:我还没注意。。。提醒大家，函数原型记得要写，并且记得加；（分号）！！！！         
参考代码:

#include <stdio.h>

#include <math.h>

void girl_1(double a,double b,double c);

void girl_2(double a,double b,double c);

void girl_3(double a,double b,double c);

int main(void)

{

    double a,b,c;

    double x1,x2;

    scanf("%lf %lf %lf",&a,&b,&c);

    double test=b*b-4*a*c;

    int number;

    if(test>0)

        girl_1(a,b,c);

    else if(test==0)

        girl_2(a,b,c);

    else number=3;

        girl_3(a,b,c);

            return 0;

}

void girl_1(double a,double b,double c)

{

    double x1,x2;

    double test=sqrt(b*b-4*a*c);

    double part=sqrt(b*b-4*a*c);

    x1=(-b+part)/(2*a);

    x2=-(b+part)/(2*a);

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

}

void girl_2(double a,double b,double c)

{

    double x1,x2;

    x1=x2=(-b)/(2*a);

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

}

void girl_3(double a,double b,double c)

{

    double test=sqrt(4*a*c-b*b);

    double Re=(-b)/(2*a);

    printf("x1=%.3lf+%.3lfi x2=%.3lf-%.3lfi",Re,test/(2*a),Re,test/(2*a));

}