fig23_12.c

来自「经典vc教程的例子程序」· C语言 代码 · 共 40 行

/* Writing to a random access file */
#include <stdio.h>

struct clientData {
   int acctNum;
   char lastName[15];
   char firstName[10];
   float balance;
};

main()
{
   FILE *cfPtr;
   struct clientData client;

   if ((cfPtr = fopen("credit.dat", "r+")) == NULL)
      printf("File could not be opened.\n");
   else {
      printf("Enter account number"
             " (1 to 100, 0 to end input)\n? ");
      scanf("%d", &client.acctNum);

      while (client.acctNum != 0) {
         printf("Enter lastname, firstname, balance\n? ");
         scanf("%s%s%f", &client.lastName, 
               &client.firstName, &client.balance);
         fseek(cfPtr, (client.acctNum - 1) * 
               sizeof(struct clientData), SEEK_SET);
         fwrite(&client, sizeof(struct clientData), 1, cfPtr);
         printf("Enter account number\n? ");
         scanf("%d", &client.acctNum);
      }
   }

   fclose(cfPtr);

   return 0;
}