我有两个.dat（ascii）文件。两者都排序了。
1：包含的客户端文件;帐号，姓名，余额 2：包含的事务文件;帐号，日期，销售额（交易金额）
我想要完成的是创建一个新的更新客户端文件，该文件根据添加或减去匹配交易的销售额来更新客户的余额。
到目前为止，我的代码可以让我：
1：如果客户端的事务不超过一个，则代码运行完美地将.dat文件与客户端及其更新的余额一起写入。
2：如果客户有多个交易我的代码几乎完美运行，因为它会在屏幕上打印更新的客户和帐户，例如：
1詹姆斯540.00 2约翰762.00 3保罗414.00 4 sam 502.00
将显示，但由于john有两个事务，所以包含
时创建的.dat文件1詹姆斯540.00 2约翰662.00 2约翰762.00 3保罗414.00 4 sam 502.00
我的问题在于，我需要找到一种方法让创建的.dat只为每个客户端包含一行（帐号）
我的代码附有任何帮助将不胜感激。
#include <stdio.h>
#include <string.h>
int main(void)
{
int account, matches=0; /* account number */
char date[ 30 ]; /* account Date */
double balance, saleamount,total=0, temp;; /* account SaleAmount */
int transaccount;
char name [ 30 ];
char lastname[30];
int lastaccount=-1;
double lastbalance;
FILE *cfPtr; /* cfPtr = clients.dat file pointer */
FILE *ctPtr; /* cfPtr = transaction.dat file pointer */
FILE *cfPtr2; /* cfPtr2 = new client file */
cfPtr2 = fopen( "clientupdate.dat", "w" );
/* fopen opens file; exits program if file cannot be opened */
if ( ( cfPtr = fopen( "clients.dat", "r" ) ) == NULL ) {
printf( "clients could not be opened\n" );
/*fflush(stdin);*/
} /* end if */
else
if( ( ctPtr = fopen( "transactions.dat", "r" ) ) == NULL)
{
printf( "File could not be opened\n" );
/*fflush(stdin);*/
}
else { /* read account, date,name, balance and SaleAmount from files */
fscanf( cfPtr, "%d%s%lf", &account, &name, &balance );
/*fflush(stdin);*/
fscanf( ctPtr, "%d%s%lf", &transaccount, &date, &saleamount );
/*fflush(stdin);*/
printf( "%-13s%-10s%s\n", " Account", "Name", "Balance" );
printf("|----------------------------------|\n");
while( !feof(ctPtr))
{
while( !feof(cfPtr) &&matches==0 )
{
if(account == transaccount)
{
if (lastaccount != account) {
if (lastaccount != -1)
printf(" %-10d%-10s%.2lf\n", lastaccount, lastname, lastbalance);
lastaccount = account;
strcpy (lastname, name);
}
matches=1;
total=0;
temp = balance+saleamount;
total = total + temp;
balance = total;
lastbalance = balance;
}
else
{
fscanf( cfPtr, "%d%s%lf", &account, &name, &balance );
/*fflush(stdin);*/
}
}
fprintf( cfPtr2, "%d %s %.2lf\n", account, name, total );
fscanf( ctPtr, "%d%s%lf", &transaccount, &date, &saleamount );
/*fflush(stdin);*/
matches=0;
}
}
if (lastaccount != -1)
printf(" %-10d%-10s%.2lf\n", lastaccount, lastname, lastbalance);
fclose( cfPtr2 );
getchar();
return 0;
}
答案 0 :(得分：1)
正如所承诺的，这是一个父子更新的快速例子。我没有打扰检查文件打开错误，因为你已经在代码中使用了它们，并且真正的应用程序需要检查的不仅仅是ffcanf的EOF，以便检测无效的文件格式。
#include <stdlib.h>
#include <stdio.h>
#define bool int
#define false 0
#define true !false
#define MAX_ACCOUNT_NUMBER 99999
typedef struct
{
int accountNumber;
char accountName[30];
float accountTotal;
} ClientRecordType;
typedef struct
{
int accountNumber;
char transactionDate[30];
float transactionAmount;
} TransactionRecordType;
FILE *oldClientFile;
FILE *newClientFile;
FILE *transactionFile;
void getNextClient(FILE *p_clientFile, ClientRecordType *p_clientRecord)
{
if (EOF == fscanf(p_clientFile, "%d%s%f",
&p_clientRecord->accountNumber,
&p_clientRecord->accountName,
&p_clientRecord->accountTotal))
p_clientRecord->accountNumber = MAX_ACCOUNT_NUMBER;
}
void getNextTransaction(FILE *p_transactionFile,
TransactionRecordType *p_transactionRecord)
{
if (EOF == fscanf(p_transactionFile, "%d%s%f",
&p_transactionRecord->accountNumber,
&p_transactionRecord->transactionDate,
&p_transactionRecord->transactionAmount))
p_transactionRecord->accountNumber = MAX_ACCOUNT_NUMBER;
}
void writeUpdatedClientRecord(FILE *p_newClientFile,
ClientRecordType *p_clientRecord)
{
fprintf(p_newClientFile, "%d %s %.2f ",
p_clientRecord->accountNumber,
p_clientRecord->accountName,
p_clientRecord->accountTotal);
}
bool performTransactionUpdate(FILE *p_oldClientFile,
FILE *p_newClientFile,
FILE *p_transactionFile)
{
ClientRecordType clientRecord;
TransactionRecordType transactionRecord;
getNextClient(p_oldClientFile, &clientRecord);
getNextTransaction(p_transactionFile, &transactionRecord);
while (MAX_ACCOUNT_NUMBER != clientRecord.accountNumber)
{
if (clientRecord.accountNumber == transactionRecord.accountNumber)
{
clientRecord.accountTotal += transactionRecord.transactionAmount;
getNextTransaction(p_transactionFile, &transactionRecord);
}
else if (clientRecord.accountNumber < transactionRecord.accountNumber)
{
writeUpdatedClientRecord(p_newClientFile, &clientRecord);
getNextClient(p_oldClientFile, &clientRecord);
}
else
{
return false;
}
}
if (MAX_ACCOUNT_NUMBER != transactionRecord.accountNumber) return false;
return true;
}
int main(int argc, char *argv[])
{
oldClientFile = fopen("clients.dat", "r");
newClientFile = fopen("newclients.dat", "w");
transactionFile = fopen("transactions.dat", "r");
if (performTransactionUpdate(oldClientFile,
newClientFile,
transactionFile))
printf("\nUpdate completed without errors!\n");
else
printf("\nUnsorted files or invalid transactions encountered\n");
close(newClientFile);
close(oldClientFile);
close(transactionFile);
return 0;
}
答案 1 :(得分：0)
一种典型的方法是将客户端文件加载到内存中，针对每个客户端处理事务文件，然后将客户端数据转储回磁盘。
如果您更喜欢以旧方式做事，您当然可以在处理之前将交易文件排序为客户订单。
答案 2 :(得分：0)
我最后得到了一个答案的帮助，一位同学提出了这个工作代码。感谢您帮助我弄清楚如何使其正常工作。
#include <stdio.h>
#include <string.h>
int main(void)
{
int account; /* account number */
char date[ 30 ]; /* account Date */
double balance, saleamount; /* account SaleAmount */
int transaccount;
char name [ 30 ];
int newaccount;
char newname[ 30];
double newbalance;
int match=0;
FILE *cfPtr; /* cfPtr = clients.dat file pointer */
FILE *ctPtr; /* cfPtr = transaction.dat file pointer */
FILE *cfPtr2; /* cfPtr2 = new client file */
cfPtr2 = fopen( "clientupdate.dat", "w" );
/* fopen opens file; exits program if file cannot be opened */
if ( ( cfPtr = fopen( "clients.dat", "r" ) ) == NULL ) {
printf( "clients could not be opened\n" );
} /* end if */
else
if( ( ctPtr = fopen( "transactions.dat", "r" ) ) == NULL)
{
printf( "File could not be opened\n" );
}
else { /* read account, date,name, balance and SaleAmount from files */
fscanf( cfPtr, "%d%s%lf", &account, &name, &balance );
fscanf( ctPtr, "%d%s%lf", &transaccount, &date, &saleamount );
fscanf( cfPtr2, "%d%s%lf", &newaccount, &newname, &newbalance );
while ( !feof( cfPtr ) )
{
transaccount=1;
newbalance=balance;
while ( !feof( ctPtr ) )
{
if(transaccount==account&&match==0)
{
newbalance = balance + saleamount;
match++;
}
else
if(transaccount==account&&match>0)
newbalance = newbalance + saleamount;
fscanf( ctPtr, "%d%s%lf", &transaccount, date, &saleamount );
}
rewind( ctPtr);
match=0;
fprintf( cfPtr2, "%d %s %.2f\n", account, name, newbalance );
fscanf( cfPtr, "%d%s%lf", &account, name, &balance );
}
rewind( cfPtr2);
}
fclose( cfPtr2 );
fclose( cfPtr );
fclose( ctPtr );
getchar();
return 0;
}