In this article, you will learn how to represent an algorithm using a pseudo code and elements of pseudo codes. Learning a programming language is not necessary to understand pseudo code, but knowing a programming language like C, Pascal, etc. help you understand the pseudo codes better.
Algorithms Components
The algorithm has two part – heading and the body. See the table below for more information.
| Notation | Description | |
|---|---|---|
| Heading | Algorithm <Name>(<parameter-list>) | has the name of the procedure and parameters |
| Body | { } | two braces indicates block of statements |
Example:
Algorithm Find_Max( A[n])
{
// A[n] is the list of unsorted numbers from which
// we need to find Max value.
max := 0;
for i := i to n do
if max >= A[i] then
{
max := A[i];
}
}The above is sample algorithm to find max value from a list of numbers. The algorithm is written in pseudo code and contains lot of elements with their own notations.
Notations
See the table below to understand each notation because you need them for writing algorithms.
| Element Name | Notation | Description |
| Comments | // | start with // till the end of line. |
| Block | { } | indicate a block of statements. |
| Identifier | dummy-variable | starts with a letter, variable data type is not defined. |
| Assignments | <var> := <value> | assignments are done using := operator |
| Logical Operators | and , or , not | can use logical operators in expressions. |
| Relational Operators | >, <, <=, >=, != | relational operators are allowed |
| Single Dimensional Array | A[j] | jth element of single dimensional array |
| Multi-Dimensional Array | A[i, j] | represents a multidimensional array, (i, j) th element. |
| While loop | while <condition > do { } | a while loop structure |
| For loop | for var:= value 1 to value 2 step do { } | a for loop structure |
| Conditional statement if – then | if <condition> then <statement> | if block of statements |
| Conditional statement if – then – else | if <condition> then <statement> else <statement> | if – else block of statements |
| Input | read | command to read input values |
| Output | write | command to write output values |
| Node | node = record { data type 1 data1; data type 2 data2; node *link; } | A compound data type make of other data types |