Pointers & Arrays

Pointer Arithmetic Some weirdness:

Pointer Arithmetic Adding 1 to pointer moves it one element: 0x116 Address Identifier Value 0x116 0x115 0x114 0x113 0x112 0x111 0x110 0x109 0x108 0x107 x 5 0x106 0x105 0x104 0x103 p 0x102 0x101 0x100

Pointer Arithmetic Adding 1 to pointer moves it one element: 0x116 Address Identifier Value 0x116 0x115 0x114 0x113 0x112 0x111 0x110 0x109 0x108 0x107 x 5 0x106 0x105 0x104 0x103 p 0x102 0x101 0x100

Pointer Arithmetic Adding 1 to pointer moves it one element: 0x116 Address Identifier Value 0x116 0x115 0x114 0x113 0x112 0x111 x 2.5 0x110 0x109 0x108 0x107 0x106 0x105 0x104 0x103 p 0x102 0x101 0x100

Pointer Arithmetic Adding 1 to pointer moves it one element: Size of element determines size of move Address Identifier Value 0x116 0x115 0x114 0x113 0x112 0x111 x 2.5 0x110 0x109 0x108 0x107 0x106 0x105 0x104 0x103 p 0x102 0x101 0x100

Arrays Arrays stored as base address int quiz[3]; quiz : 0x100 0x116 Identifier Value 0x116 0x115 0x114 0x113 0x112 0x111 quiz[2] 8 0x110 0x109 0x108 0x107 quiz[1] 5 0x106 0x105 0x104 0x103 quiz[0] 10 0x102 0x101 0x100

Arrays Subscript indicates elements to skip forward cout << quiz[2]; quiz[2] quiz + 2 ints 0x100 + 8 = 0x108 Address Identifier Value 0x116 0x115 0x114 0x113 0x112 0x111 quiz[2] 8 0x110 0x109 0x108 0x107 quiz[1] 5 0x106 0x105 0x104 0x103 quiz[0] 10 0x102 0x101 0x100

Arrays almost = Pointers Array : base address of contiguous list of one type of data Pointer : memory address for one type of data

Access Array Can access array as pointer Pointer arithmetic to get other elements int nums[3] = {5,6,7}; cout << *nums << endl; cout << *(nums + 1) << endl; cout << *(nums + 2) << endl;

Access Pointer Can use subscript on pointer Accessing elements after first may not be smart

Arrays almost = Pointers Anywhere you need an array you can use a pointer:

Error Why this message talks about int*

Returning a New array Can't return array from function: But can return pointer to where array starts:

Returning a New array Function to return new array containing even numbers: