程序太不健壮啦．


#include<stdio.h>
#include<math.h>

int sqr(int y);
int main()
{
long a,b,c,k;
double x1,x2;
double r;
printf("\nplease input three bits:\n");
scanf("%d %d %d",&a,&b,&c);
printf("\nthe fangcheng is : %dxx+%dx+%d=0\n",a,b,c);
k=b*b-4*a*c;
if(k>=0)
{r=sqrt(k);
x1=((-b)+r)/(2*a);
x2=((-b)-r)/(2*a);
printf("\nthe result are: %f %f\n",x1,x2);}
else
printf("\nit is not content for fangcheng\n");
return 0;
}

#include <stdio.h>
#include <math.h>
main()
{
float a,b,c,disc,term1,term2,x1,x2;
printf("input a,b,c:");
scanf("%f%f%f",&a,&b,&c);
if(a==0)
if(b==0)
if(c==0)
printf("very answers!\n");
else
printf("no answer!\n");
else
printf("have a single root=%f\n",-c/b);
else
{
disc=b*b-4*a*c;
term1=-b/(2*a);
term2=sqrt(fabs(disc))/(2*a);
if(disc<0.0)

printf("have the complex root:\n real part=%f,imag part=%f\n",term1,term2);

else
printf("x1=%f\n",term1+term2);
printf("x2=%f\n",term1-term2);
}
}