# C++ ## Pointers ```cpp // delclaring pointers int* ptr; // default value 0 when printed int var; // live in an address 0xA, think of it as empty container int var = 7; // assignment of 7 into the var container ``` * **What is a `Identity Matrix`** * * A square matrix in which all the elements of the principal diagonal are ones and all other elements are zeros. The effect of multiplying a given matrix by an identity matrix is to leave the given matrix unchanged. * **What is a `Pointer`:** * A variable that stores the memory address as its value. A pointer variable points to a data type (like int or string) of the same type, and is created with the \* operator. The address of the variable you're working with is assigned to the pointer: — [w3schools](https://www.w3schools.com/cpp/cpp_pointers.asp) --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.nosleepcreative.com/dev/archive/c++-1.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.