1058：求一元二次方程-信息學(xué)奧賽一本通
#include<algorithm>
#include<cmath>
#include<cstdio>
#include<iostream>
using namespace std;
int main(){
double a,b,c,x1,x2,delta,zero=0.000001;
cin>>a>>b>>c;
delta=b*b-4*a*c;
// delta<0
if(delta<-zero){
cout<<"No answer!";
}
//-0.000001 <= delta <= 0.000001
else if(fabs(delta)<=zero){
x1=-b/(2*a);
printf("x1=x2=%.5lf",x1);
}
else{
x1=(-b+sqrt(delta))/(2*a);
x2=(-b-sqrt(delta))/(2*a);
if(x1<x2){
printf("x1=%.5lf;x2=%.5lf",x1,x2);
}
else{
printf("x1=%.5lf;x2=%.5lf",x2,x1);
}
}
return 0;
}
標(biāo)簽：信息學(xué)奧賽一本通
