求一元二次方程ax2+bx+c=0的解。。
程序如下：

#include<stdio.h>
#include<math.h>
void main()
{
    float a,b,c,disc,x1,x2,realpart,imagpart;
    scanf("%f,%f,%f",&a,&b,&c);
    printf("the equation");
    if(fabs(a)<=1e-6)
        printf("is not a quadratic\n");
    else
    {
        disc=b*b-4*a*c;
        if(fabs(disc)<=1e-6)
            printf("has two equal roots:%8.4f\n",-b/(2*a));
        else
            if(disc>1e-6)
        {
            x1=(-b+aqrt(disc))/(2*a);
            x2=(-b-aqrt(disc))/(2*a);
            printf("has distinct real roots:%8.4f and %8.4f\n",x1,x2);
        }
        else
        {
            realpart=-b/(2*a);
            imagpart=sqrt(-disc)/(2*a);
            printf("has complex roots:\n");
            printf("%8.4f+%8.4fi\n",realpart,imagpart);
            printf("%8.4f-%8.4fi\n",realpart,imagpart);
        }
    }
}


编译的时候是正确的，但是组建的时候出现一个错误如下（文件名叫li5_6）：

Linking...
li5_6.obj : error LNK2001: unresolved external symbol _aqrt
Debug/li5_6.exe : fatal error LNK1120: 1 unresolved externals
执行 link.exe 时出错.

li5_6.exe - 1 error(s), 0 warning(s)


那个高手帮忙看看是什么原因呢？谢谢啦。

谢谢谢谢。。我检查好几遍了都没检查出来。。呵呵~