Array Declaration and Indexing

Array Declaration

• In pseudocode, a 1D array is declared using the following syntax: array-name[ size ]
• array-name is the name given to the array
• size is the number of elements the array can hold
• Example: scores[5] declares an array named scores that can hold 5 elements

Array Indexing

• Array elements are accessed using an index, which is a numerical value that corresponds to a specific position in the array
• Indexing starts at 0, meaning the first element is at index 0, the second element is at index 1, and so on
• To access an element, use the following syntax: array-name[ index ]
• Example: scores[2] accesses the third element in the scores array (since indexing starts at 0)

Array Operations

• Assignment: Assign a value to an array element using the following syntax: array-name[ index ] ← value
• Example: scores[2] ← 90 assigns the value 90 to the third element in the scores array
• Reading: Read the value of an array element using the following syntax: variable ← array-name[ index ]
• Example: total ← scores[2] reads the value of the third element in the scores array and assigns it to the variable total

Array Traversal

• For Loop: Traverse an array using a for loop, which iterates over each element in the array
• Syntax: FOR index FROM 0 TO size - 1 DO ... END FOR
• Example:

FOR i FROM 0 TO 4 DO
  OUTPUT scores[i]
END FOR

This code outputs each element in the scores array.

• While Loop: Traverse an array using a while loop, which iterates over each element in the array
• Syntax: index ← 0; WHILE index < size DO ... index ← index + 1 END WHILE
• Example:

i ← 0
WHILE i < 5 DO
  OUTPUT scores[i]
  i ← i + 1
END WHILE

This code outputs each element in the scores array.

Array Declaration

• A 1D array is declared using the syntax array-name[ size ], where array-name is the name of the array and size is the number of elements it can hold.
• Example: scores[ 5 ] declares an array named scores that can hold 5 elements.

Array Indexing

• Array elements are accessed using an index, which is a numerical value corresponding to a specific position in the array.
• Indexing starts at 0, meaning the first element is at index 0, the second element is at index 1, and so on.
• The syntax for accessing an element is array-name[ index ].
• Example: scores[ 2 ] accesses the third element in the scores array.

Array Operations

• Assignment: A value is assigned to an array element using the syntax array-name[ index ] ← value.
• Example: scores[ 2 ] ← 90 assigns the value 90 to the third element in the scores array.
• Reading: The value of an array element is read using the syntax variable ← array-name[ index ].
• Example: total ← scores[ 2 ] reads the value of the third element in the scores array and assigns it to the variable total.

Array Traversal

Using For Loop

• A for loop is used to traverse an array, iterating over each element in the array.
• The syntax for a for loop is FOR index FROM 0 TO size - 1 DO...END FOR.
• Example: FOR i FROM 0 TO 4 DO OUTPUT scores[ i ] END FOR outputs each element in the scores array.

Using While Loop

• A while loop is also used to traverse an array, iterating over each element in the array.
• The syntax for a while loop is index ← 0; WHILE index < size DO...index ← index + 1 END WHILE.
• Example: i ← 0; WHILE i < 5 DO OUTPUT scores[ i ]; i ← i + 1 END WHILE outputs each element in the scores array.

Array Declaration

• A 1D array is declared using the syntax array-name[ size ], where array-name is the name given to the array and size is the number of elements it can hold.
• Example: scores[ 5 ] declares an array named scores that can hold 5 elements.

Array Indexing

• Array elements are accessed using an index, which is a numerical value that corresponds to a specific position in the array.
• Indexing starts at 0, meaning the first element is at index 0, the second element is at index 1, and so on.
• The syntax to access an element is array-name[ index ].
• Example: scores[ 2 ] accesses the third element in the scores array.

Array Operations

• Assignment: Assign a value to an array element using array-name[ index ] ← value.
• Example: scores[ 2 ] ← 90 assigns the value 90 to the third element in the scores array.
• Reading: Read the value of an array element using variable ← array-name[ index ].
• Example: total ← scores[ 2 ] reads the value of the third element in the scores array and assigns it to the variable total.

Array Traversal

• For Loop: Traverse an array using a for loop, which iterates over each element in the array.
• The syntax is FOR index FROM 0 TO size - 1 DO...END FOR.
• Example:

FOR i FROM 0 TO 4 DO
  OUTPUT scores[i]
END FOR

This code outputs each element in the scores array.

• While Loop: Traverse an array using a while loop, which iterates over each element in the array.
• The syntax is index ← 0; WHILE index < size DO...index ← index + 1 END WHILE.
• Example:

i ← 0
WHILE i < 5 DO
  OUTPUT scores[i]
  i ← i + 1
END WHILE

This code outputs each element in the scores array.