编译后出现scanf was not declared in this scope

Question

#include<math.h>
int main()
{
double a,b,c,x1,x2,disc,q,p;
scanf("a=%lf,b=%lf,c=%lf",&a,&b,&c);
p=-b/(2a);
disc=bb-4ac;
q=sqrt(disc)/(2*a);
x1=p+q;
x2=p-q;
printf("\nx1=%5.2lf\nx2=%5.2lf\n",x1,x2);
return 0;
}

Answer 1

#include<stdio.h>
少了库文件。

#include<stdio.h>
#include<math.h>
int main()
{
double a,b,c,x1,x2,disc,q,p;
scanf("a=%lf,b=%lf,c=%lf",&a,&b,&c);
p=-b/(2*a);
disc=b*b-4*a*c;
q=sqrt(disc)/(2*a);
x1=p+q;
x2=p-q;
printf("\nx1=%5.2lf\nx2=%5.2lf\n",x1,x2);
return 0;
}