如何计算文件中的生物数量？

Question

我已经尽力想尽一切办法，已经尝试过Chegg和Google，但是我仍然坚持获取文件中生物的数量。我尝试过for和while循环，只应该是两行代码。我什至无法获得更多。

#include <iostream>
#include <cstdlib>
#include <string>
#include <vector>
#include <fstream>
#include <algorithm>
#include <iomanip>
using namespace std;

// Global variables
const int CREATURE_NAME_SIZE = 30;          // Max length of a creature name
const int CREATURE_TYPE_SIZE = 26;          // Max length of a creature type
const string FILENAME = "creatures.dat";    // Name of file that contains the data

// struct used to create records in file
struct Creature
{
    char name[CREATURE_NAME_SIZE];              // Name of the creature
    char creatureType[CREATURE_TYPE_SIZE];      // Type of creature
    int hp;                                     // Hit points for creature
    int armor;                                  // Armor class for creature
    int speed;                                  // Speed of creature
};

// This function returns true if the name of the left creature is less than the name of the right creature
// Use this function when running the sort function
bool sortByName(const Creature &lhs, const Creature &rhs)
{
    string name1(lhs.name), name2(rhs.name);
    return name1 < name2;
}

// Function declarations
// You will need to code the definitions for each of these functions
int getCreatureNumber(int numCreatures);
void displayCreature(fstream& file, int num);
void displaySorted(fstream& file);

int main()
{
    char choice;            // choice made by user for menu
    fstream creatureFile;   // file stream for input file
    int numCreatures;       // the number of creatures saved to the file

    // Open the creatureFile for input and binary (one statement of code)
    creatureFile.open(FILENAME, ios::out | ios::in | ios::ate | ios::binary);

    // Get the number of creatures in the file (two statements of code)
    // The number of creatures should be assigned to numCreatures

Answer 1

这可能应该起作用

Creature creature;
while(!creatureFile.eof())
{
    creatureFile.read((char *)&creature, sizeof(creature));
    numCreatures++;
}
cout<<"Count is : "<<numCreatures;

循环检查文件结尾。

read（）从生物.dat中读取一个生物大小的结构。