Providing default values to dynamic array to class in C++

Question

/* Hello Friends ... I am a beginner in C++ */

#include<iostream>
#include<conio.h>
using namespace std;

class A
{
    protected:
        int a,b;
    public:
        A():a(0),b(0){   }

};

int main()
{

 A *x;
 x = new A[20];
delete []x;
getch();
return 0;
}

My question is, How do we create a parameterised Constructor in Class A such that I could pass some default values while dynamically creating the array without using for loop. Also please tell me,What is the syntax of passing those values?

similar stackoverflow.com/questions/779655/…

Deepak
– Deepak

2013-11-01 05:10:45 +00:00
Commented Nov 1, 2013 at 5:10 — Deepak
– Deepak, Commented Nov 1, 2013 at 5:10

AliciaBytes · Accepted Answer · 2013-11-01 04:44:42Z

0

I think what you want is this:

#include<iostream>
#include<conio.h>
using namespace std;

class A
{
    protected:
        int a,b;
    public:
        A():a(0),b(0){   }
        A(int a, int b) : a(a), b(b) {  }

};

int main()
{
    A *x;
    x = new A[3]{ {10, 5}, {1, 2}, {4, 5} };
    delete []x;
    getch();
    return 0;
}

Note that you falsely had delete []a; in your code instead of the correct delete []x;.

The Constructor A(int a, int b) : a(a), b(b) { } initializes the member a and b with the parameter a and b respectively in the parameter list.

Then for the new call you give it a list with the arguments for the constructor grouped together in curly braces like this:

x = new A[3]{ {10, 5}, {1, 2}, {4, 5} };

answered Nov 1, 2013 at 4:44

AliciaBytes

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1 Comment

Siyuan Ren Over a year ago

Note this requires a real C++11 compiler。

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