--------------------Configuration: PROG - Win32 Debug--------------------
Linking...
PROG.OBJ : error LNK2001: unresolved external symbol _isprime
Debug/PROG.exe : fatal error LNK1120: 1 unresolved externals
Error executing link.exe.

PROG.exe - 2 error(s), 0 warning(s)
-----------------------------------------------------------------------------------------------------
#include<stdio.h>
int a[300],b[300],cnt=0;
void readDat();
void writeDat();

int isP(int m)
{
 int i;
 for(i=2;i<m;i++)
     if(m%i==0) return 0;
 return 1;
}

void jsValue()
{
    int i,j;
    int temp;
    for(i=0;i<300;i++)
        if(isprime(a[i]))
        {
            b[cnt]=a[i];
            cnt++;
        }
        for(i=0;i<cnt-1;i++)
            for(j=i+1;j<cnt;j++)
                if(b[i]>b[j])
                {
                    temp=b[i];
                    b[i]=b[j];
                    b[j]=temp;
                }
 }

void main()
{
 int i;
 readDat();
 jsValue();
 writeDat();
 printf("cnt=%d\n",cnt);
 for(i=0;i<cnt;i++)
     printf("b[%d]=%d\n",i,b[i]);
}

void readDat()
{
 FILE *fp;
 int i;
 fp=fopen("IN39.DAT","r");
 for(i=0;i<300;i++)
     fscanf(fp,"%d,",&a[i]);
 fclose(fp);
}

void writeDat()
{
 FILE *fp;
 int i;
 fp=fopen("OUT39.DAT","w");
 fprintf(fp,"%d\n",cnt);
 for(i=0;i<cnt;i++)
    fprintf(fp, "%d\n",b[i]);
 fclose(fp);
}

知道了 谢各位 高手拉 呵呵