我不大懂，请大家帮我看看，到底是哪里出了错，我的DEV-C++放在 F:\新建文件夹\Dev-Cpp




#include<math.h>
#include<graphics.h>
 main()
 {
    float t;
    int x0=320,y0=240;
    int n,i,j,r;
    int x[50],y[50];
    int gdriver=DETECT,gmode;
    printf("input n(23-31)and r(100-200)\n");   
    scanf("%d%d",&n,&r);
    initgraph(&gdriver,&gmode,"");
    cleardevice();
    setbkcolor(WHITE);
    setcolor(RED);
    t=6.28318/n;
    for(i=0;i<n;i++)
     {
       x[i]=r*cos(i*t)+x0;
       y[i]=r*sin(i*t)+y0;              
      }  
      for(i=0;i<=n-2;i++)
      {
        for(j=i+1;j<=n-1;j++)
           line(x[i],y[i],x[j],y[j]);                  
       }
       getch();
       closegraph();
  }






\新建文件夹\美丽宝石图案.cpp F:\新建文件夹\F graphics.h: No such file or directory.
 F:\新建文件夹\美丽宝石图案.cpp In function `int main()':
9 F:\新建文件夹\美丽宝石图案.cpp `DETECT' undeclared (first use this function)
                     (Each undeclared identifier is reported only once for each function it appears in.)
10 F:\新建文件夹\美丽宝石图案.cpp `printf' undeclared (first use this function)
11 F:\新建文件夹\美丽宝石图案.cpp `scanf' undeclared (first use this function)
12 F:\新建文件夹\美丽宝石图案.cpp `initgraph' undeclared (first use this function)
13 F:\新建文件夹\美丽宝石图案.cpp `cleardevice' undeclared (first use this function)
14 F:\新建文件夹\美丽宝石图案.cpp `WHITE' undeclared (first use this function)
14 F:\新建文件夹\美丽宝石图案.cpp `setbkcolor' undeclared (first use this function)
15 F:\新建文件夹\美丽宝石图案.cpp `RED' undeclared (first use this function)
15 F:\新建文件夹\美丽宝石图案.cpp `setcolor' undeclared (first use this function)
19 F:\新建文件夹\美丽宝石图案.cpp [Warning] converting to `int' from `double'
20 F:\新建文件夹\美丽宝石图案.cpp [Warning] converting to `int' from `double'
25 F:\新建文件夹\美丽宝石图案.cpp `line' undeclared (first use this function)
27 F:\新建文件夹\美丽宝石图案.cpp `getch' undeclared (first use this function)
28 F:\新建文件夹\美丽宝石图案.cpp `closegraph' undeclared (first use this function)

那我该怎么修改才能在DVE-C++下通过编译呢？
你帮我改一下吗？

你学C用的是什么编译器？我是不是也该换一下编译器了，很多都编译不出来，很没劲