选择结构和条件判断-c语言学习笔记

// 选择结构和条件判断.cpp : Defines the entry point for the console application.
#include  "stdafx.h"
#include <stdio.h>
#include <math.h>
int main()
{
	float a,b,c,disc,x1,x2,p,q;
	scanf("%f%f%f",&a,&b,&c);
	disc=b*b-4*a*c;
	if(disc<0)
		printf("this equation hasn't real roots\n");
	else
	{
		p=-b/(2.0*a);
		q=sqrt(disc)/(2.0*a);
		x1=p+q;x2=p-q;
		printf("real roots:\nx1=%7.2f\nx2=%7.2f\n",x1,x2);
	}
	return 0;
}