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Arrays and Strings

What is an array?

An array is used to store many elements of the same type in contiguous blocks of memory

Creating Uninitialized Arrays

An uninitialized array is created as follows:

type arr[array_size];

Creating an Initialized Array

An initialized array is created as follows:

type arr[] = {element1, element2, element3, …};

Accessing Array Elements

You can access the array element at index idx as follows:


First and Last Array Elements

The first and last elements in the array can be found at the following indices:

firstElement = arr[0]; lastElement = arr[arraySize - 1];


Array size can be found using the sizeof() function

Iterating Through Arrays

Arrays can be iterated through using while loops or for loops.

Invalid Array Access

Attempting to access or modify an element at an index greater than the length of the array will cause the program to behave unpredictably.

Creating Multidimensional Arrays

Initialized and uninitialized multidimensional arrays are created as follows:

initializedMultArray = type arr[][dim2Size]…[dimNSize] = {{element1, element2,…},{element1, element2, …}, …}; uninitializedMultArray = type arr[dim1Size][dim2Size]…[dimNSize];

String Length

Arrays are static, therefore the length of a string cannot be modified.

Accessing Characters in a String

Characters in a string can be accessed and modified using indices, the same technique used with arrays.

Creating Strings

Strings can be created by initializing an array of chars.

Null Character

All strings terminate with a null character ('\0').


You can find the length of a string using the strlen() function.


Two strings can be concatenated using the strcat() function.


A string can be copied into an empty char array (empty string) using the strcpy() function.