Creating a random-access file sequentially

#include <stdio.h>
// clientData structure definition
struct clientData {
  unsigned int acctNum;  // account number
  char lastName[15];     // account last name
  char firstName[10];    // account first name
  double balance;        // account balance
};                       // end structure clientData

int main() {
  unsigned int i;  // counter used to count from 1-100
  // create clientData with default information
  struct clientData blankClient = {0, "", "", 0.0};
  FILE *cfPtr;  // credit.dat file pointer

  // fopen opens the file; exits if file cannot be opened
  if ((cfPtr = fopen("credit.dat", "wb")) == NULL) {
    puts("File could not be opened.");
  }  // end if
  else {
    // output 100 blank records to file
    for (i = 1; i <= 100; ++i) {
      fwrite(&blankClient, sizeof(struct clientData), 1, cfPtr);
    } 

    fclose(cfPtr);  // fclose closes the file
  } // end else
  puts("File created successfully");
}  // end main