Introduction

• This section is dedicated to anytime I create a quick reference quick to basic understanding of a topic in C++. All the information here can be found in two books. programming principles and practice using C++ by Bjarne Stroustrup and Data Structures and Algorithms in C++ by Michael T. Goodrich, Roberto Tamassia, David M. Mount

Memory

• Computer memory is an incredibly complicated topic but as far as us programmers are concerned, memory is just a sequence of bytes. We can number the bytes from 0 to the last one. We call such a number that indicates a location in memory an address. We can think of an address as a kind of integer value.

int  var = 15;

• The above code will set aside an int-sized piece of memory for var somewhere in the available memory and put the value 17 into that memory.

Pointer

• We can also store and manipulate addresses. An object that holds an address value is called a pointer.

int* ptr &var;

• The * is used to indicate that we are using a pointer. the &(address of operator), is used to get the address of an object. So if var is stored at address 4096, ptr will hold a value of 4096.

char ch = 'c';
char* pc = &ch;

int ii = 13;
int* pi = ⅈ

std::cout<< *pc << *pi;

• In both cases above we are defining a variable and then using the address of operator to store the actual memory address in the pointer. Next we use the dereference operator(*) to print out c and 13 to the console. The dereference operator is what we use to grab the actual value that a pointer is pointing to.

Important point

• Even though a pointer value can be an integer, a pointer is not an integer. The question, what does an integer point to is not a well formed one. Integers do not point, pointers do. A pointer type provides the operations suitable for addresses, whereas, integers provides the arithmetic and logical operations suitable for integers.

Conclusion

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