[编程入门]自定义函数求一元二次方程-题解(C语言代码)

#include<stdio.h>
#include<math.h>
int main()
{
    float a,b,c;
    scanf("%f%f%f",&a,&b,&c);
    float r=b*b-4*a*c;
    float x1,x2;
    if(r>0)
    {
        x1=(-b+sqrt(r))/(2*a);
        x2=(-b-sqrt(r))/(2*a);
        printf("x1=%.3f x2=%.3f",x1,x2);
    }
    else if(r==0)
    {
        printf("%.3f",(-b)/(2*a));
    }
    else
    {
        printf("x1=%.3f+%.3fi x2=%.3f-%.3fi",(-b)/(2*a),sqrt(-r)/(2*a),(-b)/(2*a),sqrt(-r)/(2*a));
    }
    return 0;
}