WU-C语言程序设计教程（第三版）课后习题8.2 （C语言代码）

#include<stdio.h>
#include<math.h>
void solve1(double a,double b,double c)
{
	printf("x1=%.3lf ",-b/(2*a));
	printf("x2=%.3lf ",-b/(2*a));
	printf("\n");
}
void solve2(double a,double b,double c)
{
	printf("x1=%.3lf+%.3lfi ",-b/(2*a),sqrt(4*a*c-b*b)/(2*a));
	printf("x2=%.3lf-%.3lfi",-b/(2*a),sqrt(4*a*c-b*b)/(2*a));
	printf("\n");
}
void solve3(double a,double b,double c)
{
	printf("x1=%.3lf ",(-b+sqrt(b*b-4*a*c))/(2*a));
	printf("x2=%.3lf",(-b-sqrt(b*b-4*a*c))/(2*a));
	printf("\n");
}
int main()
{
	double a,b,c,d;
	scanf("%lf%lf%lf",&a,&b,&c);
	d=b*b-4*a*c;
	if(d==0)
	solve1(a,b,c);
	if(d<0)
    solve2(a,b,c);
	if(d>0)
	solve3(a,b,c);
	return 0;
}