![ACCESSING ELEMENTS
In C++, each element in an array is associated with a number.
The number is known as an array index. Individual elements
within an array are accessed using index notation ([]).](https://image.slidesharecdn.com/arraysandpointers-240412132543-ce189f03/85/c-arrays-and-pointers-grade-9-STEP-curriculum-pptx-7-320.jpg)
![ACCESSING ELEMENTS
Consider this example:
Few Things to R emember:
The array indices start with 0. Meaning x[0] is the first element stored at index 0.
If the size of an array is n, the last element is stored at index (n-1). In this example, x[5] is the last element.
Elements of an array have consecutive addresses.](https://image.slidesharecdn.com/arraysandpointers-240412132543-ce189f03/85/c-arrays-and-pointers-grade-9-STEP-curriculum-pptx-8-320.jpg)
![POINT TO EVERY ARRAY ELEMENTS
access the elements using the single pointer
suppose if we have initialized ptr = &arr[2]; then](https://image.slidesharecdn.com/arraysandpointers-240412132543-ce189f03/85/c-arrays-and-pointers-grade-9-STEP-curriculum-pptx-56-320.jpg)
![EXAMPLE 1 : C++ POINTERS AND ARRAYS
IN THE ABO VE PR O G R AM, WE FIR ST
SIMPLY PR INTED THE ADDR ESSES O F THE
AR R AY ELEMENTS WITHO UT USING THE
PO INTER VAR IABLE PTR .
THEN, WE USED THE PO INTER PTR TO
PO INT TO THE ADDR ESS O F A[0], PTR + 1
TO PO INT TO THE ADDR ESS O F A[1], AND
SO O N.](https://image.slidesharecdn.com/arraysandpointers-240412132543-ce189f03/85/c-arrays-and-pointers-grade-9-STEP-curriculum-pptx-58-320.jpg)
c++ arrays and pointers grade 9 STEP curriculum.pptx
- 1. ARRAYS AND POINTERS IN C++ Group 6
- 2. C++ ARRAYS
- 3. An array in C++ is a data structure that stores a fixed-size sequential collection of elements of the same type. Each element in the array is accessed by its numerical index, which represents its position within the array. O nce you make an array, it can't change size. It stays the same size the whole time your program runs. Everything in an array is put in order next to each other in the computer's memory. INTRODUCTION TO ARRAYS
- 5. 01 . 02. DECLARATION ACCESSING ELLEMENTS 03. ONE DIMENSIONAL & MULTIDIMENTIONAL ARRAYS 04. INITIALIZATION 05. ARRAY SIZE KEY POINTS
- 6. DECLARATION Declaration involves specifying the type and size of the array SYNTAX EXAMPLE SYNTAX EXAMPLE int - type of element to be stored x - name of the array 6 - size of the array
- 7. ACCESSING ELEMENTS In C++, each element in an array is associated with a number. The number is known as an array index. Individual elements within an array are accessed using index notation ([]).
- 8. ACCESSING ELEMENTS Consider this example: Few Things to R emember: The array indices start with 0. Meaning x[0] is the first element stored at index 0. If the size of an array is n, the last element is stored at index (n-1). In this example, x[5] is the last element. Elements of an array have consecutive addresses.
- 9. INITIALIZATION Arrays can be initialized during declaration using initializer lists {}. Partial initialization is also allowed, with the remaining elements initialized to zero or default values. EXAMPLE ANOTHER WAY: Here, we have not mentioned the size of the array. In such cases, the compiler automatically computes the size.
- 10. INITIALIZATION In C++, if an array has a size n, we can store up to n number of elements in the array. However, what will happen if we store less than n number of elements. ARRAY WITH EMPTY MEMBERS EXAMPLE
- 11. ARRAY SIZE The size of an array is fixed and determined at compile time. It represents the total number of elements that the array can hold. The sizeof operator can be used to determine the size of an array in bytes, allowing for calculations and memory management.
- 13. ONE DIMENSIONAL ARRAYS A O ne-Dimensional Array in C++ programming is a special type of variable that can store multiple values of only a single data type such as int, float, double, char, structure, pointer, etc. at a contagious location in computer memory. Here contagious location means at a fixed gap in computer memory. A O ne-Dimensional Array is also known as 1D Array.
- 14. ONE DIMENSIONAL ARRAYS we can see that the name of the one dimensional array is a and it can store 5 integer numbers. Size of the array is 5. Index of the array is 0, 1, 2, 3 and 4. The first index is called Lower Bound, and the last index is called an Upper Bound. Upper Bound of a one dimensional is always Size – 1.
- 16. ONE DIMENSIONAL ARRAYS To store the number in each cell of the array we can use the following syntax. EXAMPLE O UTPUT We can access any number stored in a 1D array using the following syntax.
- 17. Example 1: Program to input 10 numbers in an array and display only the even numbers if present in the array. STORE AND ACCESS THE NUMBERS IN A 1 D ARRAY USING LOOPS Here, you can see that we have run a for loop 10 times to store the user's input in the array. After that we have run another for loop 10 times to access each number from the array and print only the even numbers from it.
- 18. Example 2: Program to input 5 numbers in an array and print all the numbers from the backside of the array. STORE AND ACCESS THE NUMBERS IN A 1 D ARRAY USING LOOPS Here, you can see that we have run a for loop 5 times to store the user's input in the array. After that we have run another for loop in reverse order to print all the numbers from the back side of the array.
- 19. MULTIDIMENSIONAL ARRAYS C++ supports multidimensional arrays, allowing arrays of arrays. This enables the creation of structures with multiple dimensions, such as matrices, grids, or tables, where elements are accessed using multiple indices.
- 20. MULTIDIMENSIONAL ARRAYS Here, x is a two-dimensional array. It can hold a maximum of 12 elements. We can think of this array as a table with 3 rows and each row has 4 columns as shown below.
- 21. MULTIDIMENSIONAL ARRAYS Three-dimensional arrays also work in a similar way. This array x can hold a maximum of 24 elements. We can find out the total number of elements in the array simply by multiplying its dimensions:
- 22. MULTIDIMENSIONAL ARRAYS 1. Initialization of two-dimentional array WR O NG WAY R IG HT WAY
- 23. MULTIDIMENSIONAL ARRAYS 2. Initialization of three-dimentional array R IG HT WAY WR O NG WAY
- 24. MULTIDIMENSIONAL ARRAYS EXAMPLE 1 : 2D ARRAY OUTPUT
- 25. MULTIDIMENSIONAL ARRAYS EXAMPLE 2: TAKING INPUT FOR 2D ARRAY OUTPUT
- 26. MULTIDIMENSIONAL ARRAYS EXAMPLE 3: TAKING INPUT FOR 2D ARRAY OUTPUT
- 27. POINTER ARITHMETIC AND ARRAY DECAY Arrays can decay into pointers to their first elements when passed to functions or assigned to pointers. This means that the name of the array can be treated as a pointer to its first element. Pointer arithmetic involves performing arithmetic operations on array pointers, allowing efficient traversal and manipulation of array elements.
- 28. C++ ARRAY OUT OF BOUNDS If we declare an array of size 10, then the array will contain elements from index 0 to 9. However, if we try to access the element at index 10 or more than 10, it will result in undefined behavior.
- 29. C++ POINTERS
- 30. Pointers in C++ are variables that hold memory addresses. They are used to indirectly access and manipulate data stored in memory Pointers are declared with a specific data type and can be initialized to point to the address of another variable or set to nullptr to indicate they don't currently point to anything. They play a crucial role in dynamic memory allocation, data structures, and low-level memory manipulation. INTRODUCTION TO POINTERS
- 31. SYNTAX WHILE ASSIGNING IT THE ADDRESS OF A VARIABLE
- 32. 01 . 02. DECLARATION AND INITIALIZATION ADRESS AND POINTERS 03. POINTER ARITHMETIC 04. TYPES OF POINTERS 05. POINTER TO POINTER KEY POINTS
- 33. ADDRESS IN C++ If we have a variable var in our program, &var will give us its address in the memory. For example, EXAMPLE OUTPUT
- 34. DECLARATION AND INITIALIZATION Pointers in C++ are variables that hold memory addresses. Declaration involves specifying the data type that the pointer will point to, using the asterisk ‘*’ symbol. Initialization can be done by assigning the address of a variable using the address-of operator (‘&’) or initializing it with ‘nullptr’ to indicate a null pointer.
- 35. DECLARATION AND INITIALIZATION Here is how we can declare pointers: We can also declare pointers in the following way: Let's take another example of declaring pointers. Here, we have declared a pointer pointVar and a normal variable p.
- 36. ADRESS AND POINTERS ASSIGNING ADDRESSES TO POINTERS Here, 5 is assigned to the variable var. And the address of var is assigned to the pointVar pointer with the code pointVar = &var.
- 37. ADRESS AND POINTERS GET THE VALUE FROM THE ADDRESS USING POINTERS The address of var is assigned to pointVar. We have used the *pointVar to get the value stored in that address. When * is used with pointers, it's called the dereference operator. It operates on a pointer and gives the value pointed by the address stored in the pointer. That is, *pointVar = var. Note: In C++, pointVar and *pointVar are completely different. We cannot do something like *pointVar = &var;
- 38. EXAMPLE OUTPUT ADRESS AND POINTERS
- 39. ADRESS AND POINTERS CHANGING VALUE POINTED BY POINTERS Here, pointVar and &var have the same address; the value of var will also be changed when *pointVar is changed.
- 40. EXAMPLE OUTPUT ADRESS AND POINTERS
- 41. ADRESS AND POINTERS COMMON MISTAKES WHEN WORKING WITH POINTERS Suppose we want a pointer varPoint to point to the address of var. Then,
- 42. POINTER ARITHMETIC Pointer arithmetic means performing arithmetic operations on pointers. It refers to the operations that are valid to perform on pointers. Following are the arithmetic operations valid on pointers in C++: 1. Incrementing and Decrementing Pointers 2. Addition of Constant to Pointers 3. Subtraction of Constant from Pointers 4. Subtraction of Two Pointers of the Same Type 5. Comparison of Pointers
- 43. POINTER ARITHMETIC EXAMPLE: INCREMENT AND DECREMENT OUTPUT DO NO T CO PY
- 44. POINTER ARITHMETIC EXAMPLE: ADDITION OF CONSTANT TO POINTERS OUTPUT DO NO T CO PY
- 45. POINTER ARITHMETIC EXAMPLE: SUBTRACTION OF CONSTANT FROM POINTERS OUTPUT DO NO T CO PY
- 46. POINTER ARITHMETIC EXAMPLE: SUBTRACTION OF TWO POINTERS OF THE SAME TYPE OUTPUT DO NO T CO PY
- 47. POINTER ARITHMETIC EXAMPLE: COMPARISON OF POINTERS OUTPUT DO NO T CO PY
- 48. POINTER TYPES The types of pointers are not so important. There is only one type of pointer mainly used on a large scale. That is the normal pointer. Along with that, there are two other types of pointers in C++. - Normal Pointer - Void Pointer - Null Pointer
- 49. POINTER TYPES NO R MAL PO INTER S - It is the most simple pointer declaration process. It is the foundation on which different operations of Pointer are executed. Syntax: data-type *pointer-name;
- 50. POINTER TYPES VO ID PO INTER S - It can be used in every data type. This means these pointers are declared in void form. This helps to reduce the pointer usability in the program. O nly one pointer can be used in different cases. Syntax: void *pointer-name;
- 51. POINTER TYPES NULL PO INTER S - In this case, a pointer is declared. But it will have the initial value as Null. This means a later value is going to be provided there. This is also a pre-step of the normal pointers. Sometimes a normal pointer is declared as a Null pointer. After that, the value will be provided there.
- 52. POINTER TO POINTER (DOUBLE POINTER) Double pointer is termed as the Pointer To Pointer operation in C++. Many experts call it “Pointers Pointers”. The simple definition is a pointer is pointing towards another pointer that is again pointed to a variable. G eneral Syntax: data-type **pointer-name;
- 53. POINTER TO POINTER (DOUBLE POINTER) EXAMPLE OUTPUT
- 54. POINTER TO POINTER (DOUBLE POINTER) EXAMPLE OUTPUT
- 55. In C++, Pointers are variables that hold addresses of other variables. Not only can a pointer store the address of a single variable, it can also store the address of cells of an array. Consider th ARRAY AND POINTER RELATIONSHIP
- 56. POINT TO EVERY ARRAY ELEMENTS access the elements using the single pointer suppose if we have initialized ptr = &arr[2]; then
- 58. EXAMPLE 1 : C++ POINTERS AND ARRAYS IN THE ABO VE PR O G R AM, WE FIR ST SIMPLY PR INTED THE ADDR ESSES O F THE AR R AY ELEMENTS WITHO UT USING THE PO INTER VAR IABLE PTR . THEN, WE USED THE PO INTER PTR TO PO INT TO THE ADDR ESS O F A[0], PTR + 1 TO PO INT TO THE ADDR ESS O F A[1], AND SO O N.
- 59. EXAMPLE 2: ARRAY NAME USED AS POINTER