メンバへのポインタ

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メンバへのポインタ

C++

#include <stdio.h>

#include "Student.h"
int main(int argc, char* argv[])

{

    Student Shibata("柴田望洋", 180, 80);

    Student Masuyan("増田真二", 170, 60);
    Shibata.Print();

    Masuyan.Print();

    puts("");
    printf("身長差:%d\n", Shibata.Comph(Masuyan.Height()));

    printf("体重差:%d\n", Shibata.Compw(Masuyan.Weight()));

    puts("");
    Student::compare ptr = &Student::Comph;

    printf("身長差:%d\n", (Shibata.*ptr)(Masuyan.Height()));
    ptr = &Student::Compw;

    printf("体重差:%d\n", (Shibata.*ptr)(Masuyan.Weight()));

    puts("");
    Student* P = &Masuyan;

    printf("体重差:%d\n", (P->*ptr)(Shibata.Weight()));
    return 0;

}

Student.h

class Student

{

    char    name[20];

    int     height;

    int     weight;

public:

            Student(const char*, int, int);
    char*   Name(void)          {return name;}

    int     Height(void)        {return height;}

    int     Weight(void)        {return weight;}
    int     Comph(int h)        {return height - h;}

    int     Compw(int w)        {return weight - w;}
    void    Print();
typedef

    int (Student::*compare)(int);

};

Student.cpp

#include <stdio.h>

#include <string.h>

#include "Student.h"
Student::Student(const char* n, int h, int w)

{

    strcpy(name, n);

    height = h;

    weight = w;

}
void Student::Print()

{

    printf("%s\n",           name);

    printf("  身長 = %d\n",  height);

    printf("  体重 = %d\n",  weight);

}

実行結果

R:\>lesson006\project1.exe

柴田望洋

  身長 = 180

  体重 = 80

増田真二

  身長 = 170

  体重 = 60
身長差:10

体重差:20
身長差:10

体重差:20
体重差:-20

Delphi

program Project1;
{$APPTYPE CONSOLE}
uses

  SysUtils, Student;
procedure main();

var

    Shibata:    TStudent;

    Masuyan:    TStudent;

    ptr:        TCompare;

    PMasuyan:   ^TStudent;

begin

    Shibata := TStudent.Create('柴田望洋', 180, 80);

    Masuyan := TStudent.Create('増田真二', 170, 60);
    Shibata.Print;

    Masuyan.Print;

    Writeln('');
    Writeln(Format('身長差:%d', [Shibata.Comph(Masuyan.Height)]));

    Writeln(Format('体重差:%d', [Shibata.Compw(Masuyan.Weight)]));

    Writeln('');
    ptr := Shibata.Comph;

    Writeln(Format('身長差:%d', [ptr(Masuyan.Height)]));
    ptr := Shibata.Compw;

    Writeln(Format('体重差:%d', [ptr(Masuyan.Weight)]));

    Writeln('');
    PMasuyan := @Masuyan;

    ptr      := PMasuyan^.Compw;

    Writeln(Format('体重差:%d', [ptr(Shibata.Weight)]));
    Shibata.Free;

    Masuyan.Free;

end;
begin

    main;

end.

Student.pas

unit Student;
interface

uses

  SysUtils;
type

    TStudent =  class

    private

        m_name: String;

        m_height:   Integer;

        m_weight:   Integer;

    public

        constructor Create(n:String; h:Integer; w:Integer);
        function    name():String;

        function    Height():Integer;

        function    Weight():Integer;
        function    Comph(h:Integer):Integer;

        function    Compw(w:Integer):Integer;
        procedure   Print();

    end;
    TCompare = function (x:Integer):Integer of object;
implementation

    constructor TStudent.Create(n:String; h:Integer; w:Integer);

    begin

        m_name      := n;

        m_height    := h;

        m_weight    := w;

    end;
    function TStudent.name():String;

    begin

        result := m_name;

    end;
    function TStudent.Height():Integer;

    begin

        result := m_height;

    end;
    function TStudent.Weight():Integer;

    begin

        result := m_weight;

    end;
    function TStudent.Comph(h:Integer):Integer;

    begin

        result := m_height - h;

    end;
    function TStudent.Compw(w:Integer):Integer;

    begin

        result := m_weight - w;

    end;
    procedure TStudent.Print();

    begin

        Writeln(Format('%s',         [m_name]));

        Writeln(Format('  身長= %d', [m_height]));

        Writeln(Format('  体重= %d', [m_weight]));

    end;

end.

実行結果

S:\>lesson006\project1.exe

柴田望洋

  身長= 180

  体重= 80

増田真二

  身長= 170

  体重= 60
身長差:10

体重差:20
身長差:10

体重差:20
体重差:-20