Question

我对一个正在编写的程序提出了一个非常具体的问题，这个程序是一个战舰游戏。我有提供给我的头文件，我必须在定义的头文件中实现函数定义。我将发布我的整个代码，但是，我只是在实现函数void ship::printShip() const时遇到了问题。我需要它来访问类中的类的信息，并且我有一个函数提供我在位置void print() const下使用，但是，它要我创建一个指针以访问打印下的信息。我将发布函数定义和头文件以及错误消息。

标题文件：

#ifndef BATTLESHIP_H_
#define BATTLESHIP_H_

// coordinates (location) of the ship and shots
class location{
public:
    location(); // void constructor, assigns -1 to X 
    void pick(); // picks a random location
    void fire(); // asks the user to input coordinates of the next shot
    void print() const; // prints location in format "a1"

    // returns true if the two locations match
    friend bool compare(location, location);

private:
    static const int fieldSize = 5; // the field (ocean) is fieldSize X fieldSize
    int x;  // 1 through fieldSize
    char y; // 'a' through fieldSize
};

// contains ship's coordinates (location) and whether is was sunk
class ship{
public:
    ship(); // void constructor, sets sunk=false
    bool match(location&) const; // returns true if this location matches
    // the ship's location
    bool isSunk() const { return sunk; } // checks to see if the ship is sunk
    void sink();       // sets "sunk" member variable of the ship to true
    void setLocation(const location&); // deploys the ship at the specified location
    void printShip() const; // prints location and status of the ship

private:
    location loc;
    bool sunk;
};

// contains the fleet of the deployed ships
class fleet{
public:
    void deployFleet(); // deploys the ships in random locations
    // of the ocean
    bool operational() const; // returns true if at least
    // one ship in the fleet is not sunk
    bool isHitNSink(const location &); // returns true if there was a deployed
    // ship at this location (hit) and sinks it
    // otherwise returns false (miss)
    void printFleet() const; // prints out locations of ships in fleet

private:
    static const int fleetSize = 5; // number of battleships
    int check(const location &);          // returns index of the ship 
    // that matches location
    // -1 if none match
    ship ships[fleetSize];        // battleships of the fleet
};

#endif /* BATTLESHIP_H_ */

以下是我的功能定义：

#include "battleship.h"
#include <iostream>
#include <cstdlib>
#include <ctime>

using namespace std;
const int FLEET_SIZE = 5;
const int FIELD_SIZE = 5;


void location::pick(){



        x = rand() % FIELD_SIZE;
        if (x == 0){
            x = 1;
        }
        y = rand() % FIELD_SIZE;
        switch (y)
        {

        case 0:
            y = 'A';
            break;
        case 1:
            y = 'B';
            break;
        case 2:
            y = 'C';
            break;
        case 3:
            y = 'D';
            break;
        case 4:
            y = 'E';
            break;
        }



}

void location::fire(void){

    cout << "Enter the number of the grid to fire on ";
    cin >>y;
    cout << "Enter the letter of the grid to fire on ";
    cin >> x;
}

void location::print() const{
    cout << y << x;
}

bool compare(location one,location two){
    if ((one.x == two.x)&&(one.y==two.y)){
        return true;
    }
    return false;
}

location::location(){
    x = -1;
}

void ship::setLocation(const location& location){
    loc= location;
}

bool ship::match(location& location)const{

    if (compare(loc, location)){
        return true;
    }
    return false;
}

void ship::printShip()const{
    cout << loc.print << endl;
    cout << sunk << endl;

}

void ship::sink(){
    sunk = true;
}

这是.cpp

#include "battleship.h"
#include <iostream>
#include <ctime>
#include <cstdlib>

using std::cout; using std::cin; using std::endl;


/// this is main function

const int FLEET_SIZE = 5;
const int FIELD_SIZE = 5;
int main(){
    srand(time(NULL));

    //
    // checking location object
    // 

    location mySpot, userShot;
    mySpot.pick(); // selecting a new random location

    cout << "Randomly selected location is: "; mySpot.print();

    cout << "Input location: ";
    userShot.fire(); // having user input a location

    if (compare(mySpot, userShot))
        cout << "Random location matches user input.\n";
    else
        cout << "Random location does not match user input.\n";



    //
    // checking ship object
    //



    ship myShip;

    myShip.setLocation(mySpot); // placing ship at mySpot location

    if(myShip.match(userShot))
    cout << "myShip\'s location matches user input.\n";
    else
    cout << "myShip's location does not match user input.\n";

    if(!myShip.isSunk()){
    cout << "myship is not sunk yet, sinking it.\n";
    myShip.sink();
    }

    cout << "myShip\'s status is: "; myShip.printShip();



    //
    // checking fleet object
    // 

    /* // uncomment this part once you are done debugging above code
    fleet myFleet;

    myFleet.deployFleet(); // fleet is deployed at random locations

    if(myFleet.operational())
    cout << "Some ships of myFleet are still up.\n";

    if(myFleet.isHitNSink(userShot))
    cout << "there was a ship at userShot location, no it is sunk.\n";
    else
    cout << "there was no ship at userShot location.\n";

    cout << "myFleet\'s status is: "; myFleet.printFleet();
    */
}

以下是printShip() const

的错误

Error   1   error C3867: 'location::print': function call missing argument list; use '&location::print' to create a pointer to member

如果有人可以解释我需要编辑的内容，以便printShip() const打印出所需的船舶位置。

Answer 1

您只是错过了对location::print的调用中的括号：

void ship::printShip() const {
    cout << loc.print() << endl;
    cout << sunk << endl;
}

它发生了。但是要学会识别来自编译器的消息：function call missing argument list实际上意味着：“如果你想写一个函数调用，添加一个参数列表。”并且“使用'＆amp; location :: print'创建指向成员的指针”试图告诉您替代方案，即，当您真正想要指向该方法的指针时，请使用&location::print。

<强>后来 location::print()不返回任何内容，因此您可能希望更改它。或者只是使用该调用，因为它现在打印到cout。

void ship::printShip() const {
  loc.print();
  cout << endl;
  cout << sunk << endl;
}

在类中使用类

1 个答案: