ch. 8 "Arrays" --- Gaddis Starting Out W/ C++ Early Objects

Allows you to store and work with multiple values of the same data type

It depends on the array’s data type and the number of elements

By multiplying the number of bytes needed to store an individual element by the number of elements in the array

The individual elements of an array are assigned unique subscripts. These subscripts are used to access the elemts

“hours sub zero”

The values have not been assigned to other elements of the array, question marks are used to indicate that the contents of those elemts are unknown. If an array holding numeric values is define globally, all of its elemts are initialized to zero by default

NOOOOOOOO

The number inside the brackets in an array definition is the size declarator—it specifies how many elements the array holds. The number inside the brackets in an assignment statement or any statement that works with the contents of an array is a subscript, which specifies which element is being accessed

The fact that subscript numbers can be stored in variables

1) open the file
2) Use a loop to read each item from the file
3) Store it in an array element

1) open an output file pointed to by an ofstream object
2) use a loop to step through each element of the array
3) Direct the output to the file instead of to the computer screen

C++ does not perform array bounds checking, which means that you could write a program that accidentally allows an array’s subscript to go beyond its boundaries

Array subscripts start at 0 rather than 1

When they are defined

Some instructors prefer you to begin storing the actual data in element 1 when you are modeling something in the real world that logically begins with 1

NOOOOOOO

int numbers[7] = {1, 2, 4, 8}

its elements will contain “garbage” just like other local variables

It is not necessary to offset array subscripts by 1 to locate a particular piece of data

C++ does not require a value for every element—it is possible to only initialize part of an array
(Example
int numbers[7] = {1, 2, 4, 8}
The other uninitialized elements will be set to zero

NOOOOO ILLEGAL

NOOOOO ILLEGAL

Yes; by providing an initialization list that includes a value for every element; C++ counts the number of items in the initialization list and gives the array that many elemts

int value = 5;
int value (5);
int value {5}; //Only works with C++ 11 or higher and checks //to make sure the value you are initializing matches the //data type of the variable
intvalue1 = 4.9;
intvalue2 = doubleVal;
//Both cases the fractional part of the value will be //truncated before it is assigned to the variable being //defined

It is a loop that iterates once for each element in an array. Each time the loop iterates, it copies an elements from the array to a variable

Each time the range-based loop iterates, it copies the next array element to the range variable

for(dataType rangeVariable : array)
statement;

the data type of the range variable; it must be the same as the data type of the array elements, or a type that the elements can automatically be converted to

It is the name of the range variable; receives a value of a different array element during each loop iteration; during the first loop iteration, it receives the value of the first element and so on

The name of the array on which you wish the loop to operate. the loop will iterate once for every element in the array

A statement that executes during each loop iteration; to execute more than one statement in the loop, enclose the statements in a set of curly braces

Declares val as a reference variable, so as the loop executes the val variable will contain a copy of the array element and it will be an alias for the element itself

You must assign each element of the first array, one at a time, to the corresponding element of the second array

const int SIZE = 6;
int arrayA[SIZE] = {10, 20, 30, 40, 50, 60};
int arrayB [SIZE] = { 2, 4, 6, 8, 10, 12};

for {int index = 0; index < SIZE; index++} arrayA[index] = arrayB [index];

When you use the == operator with array names, the operator compares the beginning memory addresses of the arrays, not the contents of the arrays because they have two different memory addresses;
to do this correctly, you must compare their individual elements

Strings are internally stored as arrays off characters; different from other arrays in that the elements can either be treated as a set of individual characters

As single entities

Stored as characters in contiguous bytes of memory

By placing a ‘/0’ which represents the null terminator in the byte of memory following the last character of the string; no guarantee on how string objects will be implemented

By using the same subscripts

When data items stored in two or more arrays related in this fashion

It allows an alias, or synonym, to be associated with a simple or structured data type

The arrays and entire arrays can both be passed as arguments to functions

Reference variables; give the function direct access to the original array

The function is not allowed to make changes to the array’s contents

Good idea to always use a const array parameter in any function that is not intended to modify its array element

Like several identical arrays put together; useful for storing multiple sets of data; two dimensional arrays can be initialized when they are created

It needs to know how many bytes separate the memory; the number of columns is a critical factor in this calculation

NUMBER OF ROWS IN THE ARRAY

Number of columns; outer loop iterates once for each row in the array and the inner loop iterates once for each column in the row

C++ permits arrays to have multiple dimension

You must explicitly state all but the first dimension in the parameter list

It is similar to a one-dimensional array but has some advantages compared to a standard array

It is a collection of programmer-defined data types and algorithms that are available for you to use in C++ programs; data types and algorithms are not part of the C++ language but were created in addition to the built-in data types

The data types that are defined in the STL; they are called containers because they store and organize data

Organizes data in a sequential fashion, similar to an array

Organizes data with keys which allow for rapid, random access to elements stored in the contaner

It is a sequence container that is like a one-dimensional array:
-A vector holds a sequence of values, or elements
-A vector stores its elements in contiguous memory locations
-You can use the array subscript operator [] to access individual elements in the vector

-you do not have to declare the number of elements that a vector will have
-if you add a value to a vector that is already full, the vector will automatically increase its size to accommodate the new value
-Vectors can report the number of elements they contain

#include

Vector numbers; you can also declare a starting size if you prefer:
Vector numbers (10);
The size will expand if you add more than 10 values to it

Vector set2 (set1);

This defines names as an empty vector of string objects

This defines scores as a vector of 15 ints

This defines letters as a vector of 25 characters. Each element is initialized with ‘A’

This define values2 as a vector of doubles. All the elements of values1, which is also a vector of doubles, are copied to values2

In C++ 11 this defines length as a vector of 3 ints, holding the values 12, 10, and 6

The array subscript operator []

Use the psuh_back function

This function accepts a value as an argument and stores it in a new element placed at the end of the vector—pushes the value at the “back” of the vector

Accomplished with the size member of a function

You can use the pop_back member function

Removes the last element from a vector named collection

Use the clear member function
Numbers.clear ()

Use the empty member function…the function returns true if the vector is empty and false if the vector has elements stored in it

Returns the value of the element located at position in the vector

Returns the maximum number of elements that may be stored in the vector w/o additional memory being allocated. (Not the same value as returned by the size member function)

Clears a vector of all its elements

Returns true if the vector is empty. Otherwise, it returns false

Removes the last element from the vector

Stores a value in the last element of the vector. If the vector is full or empty, a new element is created

Reverse the order of the elements in the vector (the last element becomes the first element, and the first element becomes the lsst element)

Resizes a vector to have n elements, where n is greater than the vector’s current size. If the optional value argument is included, each of the new elements will be initialized with that value

Example where vect has four elements

Returns the number in the vector

Swaps the contents of the vector with the contents of vector2

Elements