c++ - 这些 Visual Studio 2010 错误和警告的原因是什么？

Question

我不知道我从 Visual Studio 2010 收到这些错误的原因。

这是我程序中第 343 行到第 408 行的代码:

int create_den_from_img(char *img_file_name_part, int xlen, int ylen, int zlen )
{
  IplImage* imgs = 0;
  char str[80];
  unsigned char *data,*imgdata;

  /* allocating memory */
  data = (unsigned char *) malloc(xlen * ylen * zlen * sizeof(unsigned char) );
  if(data==NULL)
  {
    printf("error in allocating memory \n");
    exit(1);
  }

  /* Getting the filename & iterating through tiff images */

    for(int k = 0; k < zlen; k++)
    {   
        int count=2;
        int tmp=k+1;
        while(tmp/10)
        {
            count=count-1;
            tmp=tmp/10;
        }

        switch(count)
        {
            case 2:sprintf(str,"%s00%d.tif",img_file_name_part,k+1);
                    break;
            case 1:sprintf(str,"%s0%d.tif",img_file_name_part,k+1);
                    break;  
            default:sprintf(str,"%s%d.tif",img_file_name_part,k+1);
                    break;
        }
        printf("%s\n",str);

        /* Loading Image using OpenCV */
        imgs=cvLoadImage(str,-1);
        if(imgs==NULL)
        {
            printf("error in opening image \n");
            exit(1);
        }
        imgdata=(uchar *)imgs->imageData;

        for(int j =0; j < ylen; j++)
        {
            for(int i =0; i < xlen; i++)
            {
                data[ k*xlen*ylen + j*xlen + i ] = imgdata[ j*xlen+i ];
            }
        }

        cvReleaseImage(&imgs );
    }

    /* populating `data` variable is done. So, calling `write_den` */
    if(write_den("test.den",data,xlen,ylen,zlen)==0)
    {
        printf("Error in creating den file\n");
        exit(1);
    }
    printf("Den file created\n");

}

这些是错误列表:

Error   3   error C2143: syntax error : missing ';' before 'type'   c:\examples\denfile.c   358 1   MTP_TEST
Error   4   error C2143: syntax error : missing ';' before 'type'   c:\examples\denfile.c   358 1   MTP_TEST
Error   5   error C2143: syntax error : missing ')' before 'type'   c:\examples\denfile.c   358 1   MTP_TEST
Error   6   error C2143: syntax error : missing ';' before 'type'   c:\examples\denfile.c   358 1   MTP_TEST
Error   7   error C2065: 'k' : undeclared identifier    c:\examples\denfile.c   358 1   MTP_TEST
Error   9   error C2065: 'k' : undeclared identifier    c:\examples\denfile.c   358 1   MTP_TEST
Error   10  error C2059: syntax error : ')' c:\examples\denfile.c   358 1   MTP_TEST
Error   11  error C2143: syntax error : missing ';' before '{'  c:\examples\denfile.c   359 1   MTP_TEST
Error   12  error C2065: 'k' : undeclared identifier    c:\examples\denfile.c   361 1   MTP_TEST
Error   13  error C2065: 'k' : undeclared identifier    c:\examples\denfile.c   370 1   MTP_TEST
Error   14  error C2065: 'k' : undeclared identifier    c:\examples\denfile.c   372 1   MTP_TEST
Error   15  error C2065: 'k' : undeclared identifier    c:\examples\denfile.c   374 1   MTP_TEST
Error   16  error C2143: syntax error : missing ';' before 'type'   c:\examples\denfile.c   388 1   MTP_TEST
Error   17  error C2143: syntax error : missing ';' before 'type'   c:\examples\denfile.c   388 1   MTP_TEST
Error   18  error C2143: syntax error : missing ')' before 'type'   c:\examples\denfile.c   388 1   MTP_TEST
Error   19  error C2143: syntax error : missing ';' before 'type'   c:\examples\denfile.c   388 1   MTP_TEST
Error   20  error C2065: 'j' : undeclared identifier    c:\examples\denfile.c   388 1   MTP_TEST
Error   22  error C2065: 'j' : undeclared identifier    c:\examples\denfile.c   388 1   MTP_TEST
Error   23  error C2059: syntax error : ')' c:\examples\denfile.c   388 1   MTP_TEST
Error   24  error C2143: syntax error : missing ';' before '{'  c:\examples\denfile.c   389 1   MTP_TEST
Error   25  error C2143: syntax error : missing ';' before 'type'   c:\examples\denfile.c   390 1   MTP_TEST
Error   26  error C2143: syntax error : missing ';' before 'type'   c:\examples\denfile.c   390 1   MTP_TEST
Error   27  error C2143: syntax error : missing ')' before 'type'   c:\examples\denfile.c   390 1   MTP_TEST
Error   28  error C2143: syntax error : missing ';' before 'type'   c:\examples\denfile.c   390 1   MTP_TEST
Error   29  error C2065: 'i' : undeclared identifier    c:\examples\denfile.c   390 1   MTP_TEST
Error   31  error C2065: 'i' : undeclared identifier    c:\examples\denfile.c   390 1   MTP_TEST
Error   32  error C2059: syntax error : ')' c:\examples\denfile.c   390 1   MTP_TEST
Error   33  error C2143: syntax error : missing ';' before '{'  c:\examples\denfile.c   391 1   MTP_TEST
Error   34  error C2065: 'k' : undeclared identifier    c:\examples\denfile.c   392 1   MTP_TEST
Error   35  error C2065: 'j' : undeclared identifier    c:\examples\denfile.c   392 1   MTP_TEST
Error   36  error C2065: 'i' : undeclared identifier    c:\examples\denfile.c   392 1   MTP_TEST
Error   37  error C2065: 'j' : undeclared identifier    c:\examples\denfile.c   392 1   MTP_TEST
Error   38  error C2065: 'i' : undeclared identifier    c:\examples\denfile.c   392 1   MTP_TEST

我一整天都在收到此类错误。有时代码会编译，而有时则不会。这真的很烦人。

Answer 1

您正在编译一个 .c 文件，这对于 Microsoft Visual Studio 意味着您需要编写 C89(又名 C90)代码，而不是 C99 代码或 C++。

这意味着您必须在每个 block 的开头声明您的变量。这意味着您不能:

for (int k = 0; ...

您必须在 block 的开头声明 k 并执行:

for (k = 0; ...