【问题标题】：CSV file data in structure data for hashing with C结构数据中的 CSV 文件数据，用于使用 C 进行散列
【发布时间】：2015-09-14 07:29:13
【问题描述】：

我需要从 CSV 文件中读取一些数据并创建一个数据结构，以便创建一个哈希表。我尝试了很多，浪费了很多时间，但没有结果。请检查我的代码并帮助我找出错误所在...

这是文件数据、输出和代码。

（我一个人写了代码，在Deitel的C编程语言和Deitel书的帮助下。）

代码

#include <stdio.h>
#include <stdlib.h> 
#include <string.h>
#include <ctype.h>

struct clientData
{
   int acctNum; 

   char breaker[50]; 
   char datetime[60];
   double current;
 };

int main()
{ 
  FILE *cfPtr;

  struct clientData client = {0,"","",0.0 };
  if ( ( cfPtr = fopen("data1.csv","rb") ) == NULL)
  {
    printf("File could not be opened.\n");
  }   
  else
  {
    printf("%-6s%-16s%-11s%10s\n","Acct","Last Name","First Name","Balance");
    
    while ( !feof( cfPtr) )
    {
        fread( &client , sizeof ( struct clientData ), 1 , cfPtr );

        if ( client.acctNum !=0 )
        {
            printf ("%-6d%-16s%-11s%10.2f\n",
                    client.acctNum,client.breaker,client.datetime,client.current );
        }
    }
    fclose ( cfPtr );
  }
  return 0 ;
}

CSV 输入文件

acct,breaker,S_TimeStamp,MeasurementValue 1、EthiotideAtalantiMVBreakerBB2Q2Current,1/12/20158:30,37.6 2、EthiotideAtalantiMVBreakerBB2Q2Current,1/12/20159:00,34.2 3、EthiotideAtalantiMVBreakerBB2Q2Current,1/12/20159:30,37.2 4，EthiotideAtalantiMVBreakerBB2Q2Current，1/12/201510:00,40.6 5，EthiotideAtalantiMVBreakerBB2Q2Current，1/12/201510:30,41.8 6、Eth1iotideAtalantiMVBreakerBB2Q2Current,1/12/201511:00,45.8

输出

Acct 姓氏名字余额 1952670561,断路器,S_TimeStamp,MeasurementValue 1、EthiotideAtalantiMVBreakerBB2Q2Current,1/12/20158:30,37.6 2、EthiotideAtalantiMVBreak@talantiMVBreakerBB2Q2Current,1/12/20158:30,37.6 2，EthiotideAtalantiMVBreak @ 178724158464812467496986462827554460798109233540662154481413250685702096704425934569739618465990294960631478737616585889239313529311067888348744695823558167564353119398296863451093505908419875899425197001801728.00 11116509172Q2Current 1 /二万零一百五十九分之十二：00,34.2 3、EthiotideAtalantiMVBreakerBB2Q2Current,1/12/20159:30,37.2 4、EthiotideAtalantiMVBreakerBB2Q2C@VBreakerBB2Q2Current,1/12/20159:30,37.2 4、EthiotideAtalantiMVBreakerBB2Q2C@5155825882657381.00 1701999221nt,1/12/201510:00,40.6 5，EthiotideAtalantiMVBreakerBB2Q2Current，1/12/201510:30,41.8 6、Eth1iotideAtalantiMVBreakerBB2Q2Curren@rBB2Q2Current,1/12/201510:30,41.8 6，Eth1iotideAtalantiMVBreakerBB2Q2Curren @ 62020397019943253271215041932658580009235443368333447944639125867547040589859590642175830919754237423637956114804980964218473105282339526865630710982971497957257635386734871861549462238776468516448931338295812955819267325952.00201511分之79175179612：00,45.8 40.6 5,EthiotideAtalantiMVBreakerBB2Q2Current,1/12/201510:30,41.8 6,Eth1iotideAtalantiMVBreakerBB2Q2Curren@rBB2Q2Current,1/12/201510:30,41.8 6，Eth1iotideAtalantiMVBreakerBB2Q2Curren @ 62020397019943253271215041932658580009235443368333447944639125867547040589859590642175830919754237423637956114804980964218473105282339526865630710982971497957257635386734871861549462238776468516448931338295812955819267325952.00 P>

【问题讨论】：

CSV 仅为 chars s。您无法使用fread() 直接从中读取任何其他内容。您需要解析文本 (chars) 读取并将结果转换为特定变量，如 ints 和 doubles 或使用 fscanf()。

标签： c csv data-structures hash

【解决方案1】：

#include <stdio.h>

struct clientData{
    int acctNum; 
    char breaker[50]; 
    char datetime[60];
    double current;
};

int main(void){
    FILE *cfPtr;
    struct clientData client = {0,"","",0.0 };

    if((cfPtr = fopen("data1.csv","r")) == NULL){
        printf("File could not be opened.\n");
    } else {
        char line[96];
        printf("%-6s%-40s%-20s%10s\n", "Acct", "Breaker", "TimeStamp", "MeasurementValue");

        while(fgets(line, sizeof line, cfPtr)){
            int state = sscanf(line, "%d,%49[^,],%59[^,],%lf", &client.acctNum, client.breaker, client.datetime, &client.current);
            if(state == 4 ) {
                printf("%-6d%-40s%-20s%10.2f\n",
                    client.acctNum, client.breaker, client.datetime, client.current);
            }
        }
        fclose ( cfPtr );
    }
    return 0;
}

【讨论】：