The significance of null in VC ++ and dynamic allocation of two-dimensional arrays!

Source: Internet
Author: User
Tags define null
In the past, it was always unclear to assign null values to a pointer.

Int * P = new int [1]; P = NULL;

In fact, the system has pre-set a value 0 to null.

# Define null 0

In this way, P is equal to 0.

In addition, the previous phase made some learning on the pointer, with some knowledge. The best example of this learning is to dynamically create two-dimensional arrays:

Int n, m;

Cout <"Enter the value of N, M :";

Cin> N;

Cin> m;

Cout <Endl;

Int ** T = new int * [N];

For (INT I = 0; I <n; I ++)


T [I] = new int [m];


For (I = 0; I <n; I ++)


For (Int J = 0; j <m; j ++)

{T [I] [J] = 2;

Cout <t [I] [J];}

Cout <Endl;


I think the basic knowledge of C ++ is very poor, so now I have to make up for it! Alas ~~~~~~~~~~~~~~~

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