自定义三个函数求一元二次方程

解题思路:
分别写三个函数，fun1、fun2、fun3代表三种情况。

注意事项:

注意题干要求，用三个函数分别求b^2-4ac大于0、等于0、和小于0时的根

参考代码:

#include<stdio.h>

#include<math.h>

void fun1(int a,int b,int c);

void fun2(int a,int b,int c);

void fun3(int a,int b,int c);

int main(){

    int a,b,c;

    scanf("%d %d %d",&a,&b,&c);

    int s = b*b - 4*a*c;

    if(s>0){

      fun1(a,b,c);

    }

    if(s==0){

     fun2(a,b,c);  

    }

    if(s<0)

    fun3(a,b,c);

    return 0;

}

void fun1(int a,int b,int c){

    double x1 = (double)(-b + sqrt(b * b - 4 * a * c))/(2*a);

    double x2 = (-b - sqrt(b * b - 4 * a * c))/(2*a);

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

}

void fun2(int a,int b,int c){

    int s = b*b - 4*a*c;

    double x1 = (-b + sqrt(s))/(2*a);

    double x2 = x1;

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

}

void fun3(int a,int b,int c){

    int s = b*b - 4*a*c;

    double x1 = (double)(-b)/(2*a);

    double x2 = (double)sqrt(fabs(s))/(2*a);

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

}