将数据从csv文件读入struct，得到错误

3 回答

• 0

  你没有使用strcpy正确 . 您应该只将它与char缓冲区一起使用，而不是与整数和浮点数一起使用 .

  有关它的更多信息，请阅读man strcpy .

  回复于 2024-04-26T18:26:01+08:00
• 1

  • 错误的副本 .

  不要使用 strcpy() 将字符串复制到 int . 而是转换它 .

  // strcpy(pt[i].position, strtok(buf,","));
  char *endptr;
  pt[i].position = strtol(strtok(buf,","), &endptr, 10);
  // or 
  pt[i].position = atoi(strtok(buf,","));
  ...
  pt[i].price = strtod(strtok(NULL,","), &endptr);
  

  （注意：省略了各种错误检查）

  • 启用所有编译器警告 . 这将节省您的时间，因为您的编译器应该 grab 它 .

  • 如果您收到错误，编译时间或运行时间，请发布错误而不是将错误描述为"getting errors back" .

  回复于 2024-04-26T18:26:01+08:00
• 0

  // to extract a integer from a char buffer into a int value, use atoi() not strcpy
  // to extract a float from a char buffer into a float value, use atof(), not strcpy
  
  // the last field in a line probably does not have a trailing ',' 
  //     and the last field should already be '\0' terminated by the fgets
  //     so the code should use something else to get a pointer to the last field
  
  // the calls to strtok() should be setting a char* field from the returned value
  // then
  //    1) that value can be checked for NULL
  //    2) getting a pointer to the last field would be
  //        returnedValue+=2; 
  //        (the 2 to skip over the intervening ' ' after the converted comma
  
  // all the copying/converting of the fields need to advance the 
  //    returnedValue by 1 to skip over the leading ' ',
  //    except the first field, which has no leading ' '
  
  // the #define for 'NR' should be used in the function so as to 
  //    not overflow the available number of input fields
  
  // for most of the break; statements, you may want to add a printf 
  // so the user knows what happened
  
  // suggest:
  
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  
  #define NR           (20)
  #define MAX_NAME_LEN (20)
  
  typedef struct
  {
      int   position;
      char  name[MAX_NAME_LEN];
      float price;
      int   counter;
  } drink;
  
  
  
  void init(drink *pt)
  {
      char buf[50];
      int i = 0; // loop counter
      //int j = 0; // comment out or compiler will raise a warning about unused variable
      char * returnFromStrtok = NULL;
  
      FILE *fp = NULL;
      if( NULL == (fp=fopen("Order", "r")) )
      { // then, fopen failed
          perror( "fopen failed for: Order" );
          exit( EXIT_FAILURE );
      }
  
      // implied else, fopen successful
  
      for( i = 0; i<NR; i++)
      {
          if( NULL == fgets(buf,sizeof(buf),fp) ) break;
  
          returnFromStrtok = strtok(buf, ",");
          if( NULL == returnFromStrtok ) break;
  
          pt[i].position = atoi(returnFromStrtok);
  
          returnFromStrtok = strtok(NULL, ",");
          if( NULL == returnFromStrtok ) break;
  
          // step past leading ' '
          returnFromStrtok++;
          if( MAX_NAME_LEN <= strlen( returnFromStrtok ) )
          { // bad field, too long
               memset( pt[i].name, '*', MAX_NAME_LEN ); // indicate invalid field
          }
          else
          {
              strcpy(pt[i].name, returnFromStrtok );
          }
  
          returnFromStrtok = strtok(NULL, ",");
          if( NULL == returnFromStrtok )  break;
  
          // step past leading ' '
          returnFromStrtok++;
          pt[i].price = atof(returnFromStrtok);
  
          // +2 steps by '\0' and ','
          returnFromStrtok += strlen(returnFromStrtok)+2; 
          pt[i].counter = atoi(returnFromStrtok);
      } // end for
  } // end function: init
  

  回复于 2024-04-26T18:26:01+08:00