Chapter 6: Vectors Flashcards

Array Basics

• An array peoplePerDay has 365 elements corresponding to each day of the year.
• To assign a value to an array element, use the format array[index] = value;.

Assigning Values

• peoplePerDay[0] = 250 assigns the first element the value 250.
• peoplePerDay[1] = 99 assigns the second element the value 99.

Arithmetic Operations

• If an element's value is modified through arithmetic, e.g., peoplePerDay = 5; peoplePerDay -= 3;, it results in peoplePerDay holding a value of 2.

Indexed Assignments

• For peoplePerDay[N] = 15;, if N starts at 1, the first assignment initializes peoplePerDay[1] to 15.
• The subsequent assignment peoplePerDay[N] = peoplePerDay[N - 1] * 3; results in peoplePerDay[2] = 45.

Accessing Array Elements

• The first element of an array scoresList initialized with 10 elements is accessed via scoresList[0].
• The last element of a 10-element array is scoresList[9].

Array Indices

• For an array of size N, the last index is N - 1.
• An array with a last index of 499 has 500 elements.

Vector Basics

• A vector yearsList(4) initializes four elements, which can be accessed using the .at(index) method.
• Each yearsList.at(index) corresponds to the element at that position within the vector.

Vector Assignments

• yearsList.at(1) = 2012 assigns the second element the value 2012.
• Using curr = yearsList.at(2) assigns curr the value 2025.

Validity of Access

• Attempting to access yearsList.at(4) results in an error since valid indices for four elements are 0, 1, 2, and 3.

Accessing First Element

• The first element can be accessed with yearsList.at(0).

Content Changes

• Assigning yearsList.at(0) = yearsList.at(2) changes the first element to 2025, resulting in the vector contents being 2025, 2012, 2025, 0.

Summary of Valid Indices

• Only indices 0 to 3 are valid for a vector of size 4.