C ++ two-dimensional array initialization related application skills

In C ++ programming language, array operations are a very basic and important application technology. In this article, we will introduce the operations related to C ++ two-dimensional array initialization, so that you can master the application technology in this area. The two-dimensional array of C ++ cannot be initialized using variables. The following code is certainly not compiled:

 
 

  
  
int i=5;  
  
  
int j=4;  
  
  
int a[i][j]; 
 
 

Code like this must be the experience of many C ++ beginners like me. If the array is determined in the compilation phase, the variable cannot be used as the dimension of the array. below, we use a template class to complete the C ++ two-dimensional array initialization function.

 
 

  
  
Template <class T>
  
  
Class Array2D {
  
  
Private:
  
  
T * pData;
  
  
Int dim1;
  
  
Int dim2;
  
  
Int dim1Index;
  
  
Class Array1D {
  
  
Private:
  
  
Int length;
  
  
T * start;
  
  
Public:
  
  
Array1D (T * start, int length): length (length), start (start ){}
  
  
T & operator [] (int index ){
  
  
If (index> length ){
  
  
Throw out_of_range ("the second dimension of the array is out of bounds ");
  
  
} Else {
  
  
Return * (start + index );
  
  
}
  
  
}
  
  
};
  
  
Public:
  
  
Array2D (int dim1, int dim2 ){
  
  
This-> dim1dim1 = dim1;
  
  
This-> dim2dim2 = dim2;
  
  
Int size = dim1 * dim2;
  
  
PData = new T [size];
  
  
}
  
  
Array1D operator [] (int index ){
  
  
Return Array1D (pData + index * dim1, dim2 );
  
  
}
  
  
Void print (){
  
  
For (int I = 0; I <dim1; I ++ ){
  
  
For (int j = 0; j <dim2; j ++ ){
  
  
Cout <* (pData + dim1 * I + j) <"";
  
  
}
  
  
Cout <endl;
  
  
}
  
  
}
  
  
};
  
  
Int main (){
  
  
Int index1 = 2;
  
  
Int index2 = 2;
  
  
Array2D <int> test (index1, index2 );
  
  
Test [0] [0] = 1;
  
  
Test [0] [1] = 2;
  
  
Test [1] [0] = 3;
  
  
Test [1] [1] = 4;
  
  
Test. print ();
  
  
}
 
 

Using a template class to implement this function is a good choice in C ++ two-dimensional array initialization. However, in practice, it is rarely written in this way, this is the method provided in more than tive C ++ to demonstrate the proxy mode. Array1D exists as a proxy class.