how to create array with not constant size in cpp

To create an array with a non-constant size in C++, you can make use of dynamic memory allocation and pointers. Here are the steps to create such an array:

1. Declare a pointer variable: Start by declaring a pointer variable of the desired data type. This pointer will be used to dynamically allocate memory for the array.

cpp int* dynamicArray;

1. Allocate memory using the new keyword: Allocate memory for the array using the new keyword, along with the desired data type and the size of the array. Assign the memory address to the pointer variable.

cpp int size = 10; // Specify the size of the array dynamicArray = new int[size];

In the above example, we allocate memory for an integer array of size 10.

1. Access and manipulate the array: You can access and manipulate the elements of the dynamically allocated array using the pointer variable. The pointer behaves like a regular array, so you can use array indexing to access individual elements.

cpp dynamicArray[0] = 42; // Assign a value to the first element int element = dynamicArray[0]; // Access the value of the first element

1. Deallocate memory using the delete keyword: After you are done using the dynamically allocated array, it's important to deallocate the memory to avoid memory leaks. Use the delete[] keyword followed by the name of the pointer variable.

cpp delete[] dynamicArray;

The delete[] operator ensures that the memory allocated for the array is properly released.

By following these steps, you can create an array with a non-constant size in C++. However, it's important to note that using dynamic arrays requires manual memory management and carries the risk of memory leaks if not handled properly. Consider using standard library containers like std::vector for a safer and more convenient alternative.