CSE 100 Lecture Notes - Lecture 32: Array Data Structure, In C, Empty String
27 Apr 2018
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Chapter 8: Arrays
●Array: a variable that can store multiple values of the same type
○ The values are stored in consecutive memory locations
○ It is declared using [ ] operator
■ const int ISIZE = 5;
■ int tests[ISIZE];
● The definition
○ int tests[ISIZE]; //ISIZE is 5
● Allocates the follow memory
●
Element 0
Element 1
Element 2
Element 3
Element 4
●
● Array Terminology
○ In the definition int tests[ISIZE];
■ int is the data type of the array elements
■ tests is the name of the array
■ ISIZE, in [ISIZE], is the size declarator
● It shows the number of elements in the array
■ The size of an array is the number of bytes allocated for it
● (number of elements)*(bytes needed for each element)
● Array Terminology Examples
○ Assumes int uses 4 bytes and double uses 8 bytes
■ const int ISIZE = 5, DSIZE = 10;
■ int tests[ISIZE]; //holds 5 ints, array occupies 20 bytes
■ double volume[DSIZE]; //holds 10 doubles, array occupies 80 bytes
● 8.2 Accessing Array Elements
○ Each array element has a subscript, used to accdss the element
○ Subscripts start at 0
○
0
1
2
3
4
○
○ Array elements (accessed by array name and subscript) can be used as regualr
variables
○ Tests
0
1
2
3
4
■ tests [0] = 79;
■ cout << tests[0];
■ cin >> tests[1];
■ tests[4] = tests[0] + tests[1];
■ cout << tests; //illegal due to missing subscript
Document Summary
Array : a variable that can store multiple values of the same type. The values are stored in consecutive memory locations. It is declared using [ ] operator. Int is the data type of the array elements. Tests is the name of the array. Isize, in [isize], is the size declarator. The size of an array is the number of bytes allocated for it. It shows the number of elements in the array. (number of elements)*(bytes needed for each element) Assumes int uses 4 bytes and double uses 8 bytes. Const int isize = 5, dsize = 10; Int tests[isize]; //holds 5 ints, array occupies 20 bytes. Double volume[dsize]; //holds 10 doubles, array occupies 80 bytes. Each array element has a subscript, used to accdss the element. Array elements (accessed by array name and subscript) can be used as regualr variables. Cout << tests; //illegal due to missing subscript.
