习题3.4

#include<stdio.h>#include<math.h>int main(int argc,char* argv[]) {    double a,b,c,disc,x1,x2,p,q;    scanf("%lf %lf %lf",&a,&b,&c);    disc=b*b-4*a*c;    if(sqrt(disc)<0)    printf("方程无解\n");    else    {        p=-b/(2*a);        q=sqrt(disc/(2*a));        x1=p+q;        x2=p-q;        printf("x1=%lf\nx2=%f\n",x1,x2);    }    return 0; }