Common array operations - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is an array in C?

An array in C is a collection of elements of the same type stored in contiguous memory locations. It allows you to store multiple values under a single name and access them using an index.

beginner

How do you access the third element of an array named arr?

You access it using arr[2] because array indexing starts at 0 in C.

intermediate

How do you find the length of a statically declared array in C?

Use sizeof(arr) / sizeof(arr[0]) to get the number of elements in the array.

intermediate

How can you copy elements from one array to another in C?

You can copy elements using a loop to assign each element individually, for example:<br>

for(int i = 0; i < n; i++) { dest[i] = src[i]; }

advanced

What is the result of accessing an array out of its bounds in C?

Accessing out of bounds leads to undefined behavior. It can cause crashes or incorrect data because C does not check array bounds.

What is the index of the first element in a C array?

A 0

B 1

C -1

D Depends on the array size

In C, array indexing always starts at 0.

Which of the following correctly declares an array of 5 integers?

A int arr[5];

B int arr();

C int arr;

D array int arr[5];

The correct syntax to declare an array of 5 integers is int arr[5];.

How do you get the number of elements in a statically declared array arr?

A count(arr)

B sizeof(arr) / sizeof(arr[0])

C arr.length

D length(arr)

In C, you calculate the number of elements by dividing the total size of the array by the size of one element.

What happens if you access arr[10] when arr has only 5 elements?

A Returns last element

B Returns 0

C Compiler error

D Undefined behavior

Accessing beyond the array size causes undefined behavior in C.

Which loop is commonly used to iterate over all elements of an array?

A do-while loop

B while loop

C for loop

D switch statement

A for loop is typically used to iterate over arrays because it clearly controls the index.

Explain how to declare, initialize, and access elements of an array in C.

Think about how you store multiple values and get each one by its position.

Describe common operations you can perform on arrays in C and any risks involved.

Consider what you do with a list of items and what can go wrong if you go outside the list.