WU-C语言程序设计教程（第三版）课后习题8.2 （C语言代码）

为什么是void

请大佬帮我看看哪里有问题，老是错。
#include <stdio.h>
#include <math.h>

int main()
{
	double a,b,c,x1,x2,x;
	scanf("%lf %lf %lf",&a,&b,&c);
	x=b*b-4*a*c;
	if(x>0)
	{
		x1=(-b+sqrt(x))/(2*a);
		x2=(-b-sqrt(x))/(2*a);
		printf("x1=%.3lf x2=%.3lf",x1,x2);
	} 
	else if(x==0)
	{
		x1=-b/(2*a);
		x2=x1;
		printf("x1=%.3lf x2=%.3lf",x1,x2);
	}
	else
	{
		x=sqrt(-x);
		printf("x1=%.3lf+%.3lf*i x2=%.3lf-%.3lf*i",-b/(2*a),x/(2*a),-b/(2*a),x/(2*a));
	}
	return 0;
}

这真的是太美妙了

#include<stdio.h>
#include<math.h>
main()
{
    double a,b,c,d;
    scanf("%lf %lf %lf",&a,&b,&c);
    d=b*b-4*a*c;
    if(d==0)
	{
    printf("x1=%.3lf ",-b/(2*a));
    printf("x2=%.3lf\n",-b/(2*a));
	}
    if(d<0)
	{
    printf("x1=%.3lf+%.3lfi ",-b/(2*a),sqrt(4*a*c-b*b)/(2*a));
    printf("x2=%.3lf-%.3lfi\n",-b/(2*a),sqrt(4*a*c-b*b)/(2*a));
	}
    if(d>0)
	{
	 printf("x1=%.3lf ",(-b+sqrt(b*b-4*a*c))/(2*a));
    printf("x2=%.3lf\n",(-b-sqrt(b*b-4*a*c))/(2*a));
	}
    return 0;
}

一个函数调用
#include <stdio.h>
#include "math.h"
void root(double a,double b,double c);

int main()
{
	double a,b,c;
	scanf("%lf %lf %lf",&a,&b,&c);
	double r1,r2;
	
	root(a,b,c);

	return 0;
}

void root(double a,double b,double c)
{
	double r1,r2;
	double t=b*b-4*a*c;
	if( t>0 ){
		r1=(-b+sqrt(t))/2;
		r2=(-b-sqrt(t))/2;
		printf("r1=%.3f,r2=%.3f",r1,r2);
	}else if( t==0 ){
		r1=-b/2;
		printf("r1=r2=%.3f",r1);
	}else {
		printf("r1=%.3f+%.3fi r2=%.3f%.3fi",-b/2,sqrt(-t)/2,-b/2,-sqrt(-t)/2);
	}
}

6666

看了一圈答案，这个太优美直接了！！！！

太美了