ALGORITHM AND FLOWCHART

ALGORITHM AND FLOW CHART

Algorithm and flowchart are two types of tools to explain the process of a program. Algorithms and flowcharts are two different tools used for creating new programs, especially in computer programming. An algorithm is a step-by-step analysis of the process, while a flowchart explains the steps of a program in a graphical way.

Definition of Algorithm

To write a logical step-by-step method to solve the problem is called algorithm, in other words, an algorithm is a procedure for solving problems. In order to solve a mathematical or computer problem, this is the first step of the procedure. An algorithm includes calculations, reasoning and data processing. Algorithms can be presented by natural languages, pseudo code and flowcharts, etc.

Definition of Flowchart

A flowchart is the graphical or pictorial representation of an algorithm with the help of different symbols, shapes and arrows in order to demonstrate a process or a program. With algorithms, we can easily understand a program. The main purpose of a flowchart is to analyze different processes. Several standard graphics are applied in a flowchart:

Flowchart symbols, Name and Functions

 

The graphics above represent different part of a flowchart. The process in a flowchart can be expressed through boxes and arrows with different sizes and colors. In a flowchart, we can easily highlight a certain element and the relationships between each part. 

How to Use Flowcharts to Represent Algorithms

Now that we have the definitions of algorithm and flowchart, how do we use a flowchart to represent an algorithm?

Algorithms are mainly used for mathematical and computer programs, whilst flowcharts can be used to describe all sorts of processes: business, educational, personal and of course algorithms. So flowcharts are often used as a program planning tool to visually organize the step-by-step process of a program. Here are some examples:

Example 1: Print 1 to 20:

Algorithm:

Step 1: Initialize X as 0,

Step 2: Increment X by 1,

Step 3: Print X,

Step 4: If X is less than 20 then go back to step 2.

Flowchart representation:

Example 2: Convert Temperature from Fahrenheit (℉) to Celsius (℃)

Algorithm:

Step 1: Read temperature in Fahrenheit,

Step 2: Calculate temperature with formula C=5/9*(F-32),

Step 3: Print C,

Flowchart:

 

Conclusion

From the above we can come to a conclusion that a flowchart is pictorial representation of an algorithm, an algorithm can be expressed and analyzed through a flowchart.

An algorithm shows you every step of reaching the final solution, while a flowchart shows you how to carry out the process by connecting each step. An algorithm uses mainly words to describe the steps while a flowchart uses the help of symbols, shapes and arrows to make the process more logical.

Algorithm and its characteristics
A step-by-step method of solving a problem or making decisions, as in making a diagnosis. An established mechanical procedure for solving certain mathematical problems.
 

Properties of the algorithm

 Finiteness: An algorithm must always terminate after a finite number of steps.

Definiteness: Each step of an algorithm must be precisely defined; the actions to be carried out must be rigorously and unambiguously specified for each case.

Input: An algorithm has zero or more inputs, i.e, quantities which are given to it initially before the algorithm begins.

Output: An algorithm has one or more outputs i.e, quantities which have a specified relation to the inputs.

Effectiveness: An algorithm is also generally expected to be effective. This means that all of the operations to be performed in the algorithm must be sufficiently basic that they can in principle be done exactly and in a finite length of time.

CHARACTERISTICS OF A GOOD FLOWCHART

(i)            Should consist of standardized and acceptable symbols.
(ii)           The symbols should be correctly used according to flowcharts rules.
(iii)          Should have short, clear and readable statements written inside the symbols.
(iv)         It must have clear one starting point and one ending point.
(v)          Must flow in a logical order.
(vi)         Should have acceptable and common keywords such as READ, INPUT, PRINT or WRITE.
(vii)        Must have arrows indicating the flow of instructions.

ASSIGNMENT

1.      Draw a flowchart to calculate area of a triangle

2.      List 5 more characteristics of the flowchart.