What is algorithm?
An algorithm is a procedure or step-by-step instruction for solving a problem. They form the foundation of writing a program.
For writing any programs, the following has to be known:
- Input
- Tasks to be preformed
- Output expected
For any task, the instructions given to a friend is different from the instructions given to a computer. Let’s look at the difference between them and know how to give instructions to a computer.
Instruction to a Friend:
Step 1: Go to the College Board.
Step 2: Search for my name on the board.
Step 3: Check the rank against my name.
Instructions to the Computer:
Step 1: Go to the College Board.
Step 2: Read the first name.
Step 3: If this is my name, see rank and come back.
Step 4: Read the next name.
Step 5: Repeat the above two steps until you find my name.
Breaking down the steps into smaller steps is called algorithm.
Example:
Considering the above example, let’s break down the task into steps:
- Input – Name
- Tasks to be preformed – Search for my name
- Output expected – My rank
It is a good practice to write down the algorithm first before attempting at writing a program. Each step of the algorithm will get converted to a line or a set of lines in the programming language.
More Examples for understanding the concept of Algorithms:
Example 1: Telling A Friend How To Boil Water In A Kettle.
Let’s look at the 3 requirements for writing an algorithm for this task:
- Input – Kettle, Water
- Tasks to be preformed – Boiling water, fill up the kettle
- Output expected – Boiled water
Instructions to a Friend:
Step 1: Fill the kettle with water.
Step 2: Place it on the stove and turn on the burner.
Step 3: Turn off the burner when the water starts boiling.
Instructions to the Computer:
Step 1: Put the kettle under the tap.
Step 2: Turn on the tap.
Step 3: Check if 90% of the kettle is filled.
Step 4: If not, repeat the above step.
Step 5: Turn off the tap.
Step 6: Place the kettle in the burner.
Step 7: Turn on the burner.
Step 8: Check if the water is 100 C
Step 9: If not, repeat the above step.
Step 10: Turn off the burner.
Example 2: Shopping on M.G Road
Let’s break down the task of buying a red color shoe with a bow, from the Bata showroom. The following are the 3 requirements for writing an algorithm for this task:
- Input – Name of the shop, name of the road, color of the shoe, size of the shoe.
- Tasks to be preformed – Shopping.
- Output expected – Shoe.
The algorithm of this task for a friend is fairly easy and simple. So, let’s look at the algorithm for the computer.
Step 1: Walk to the first shop on M.G road.
Step 2: Check if this in the Bata Showroom.
Step 3: Enter the shop and ask for a red shoe size 5.
Step 4: Buy the shoe and come back.
Step 5: Go to the next shop, repeat step 2
Writing algorithms is a crucial step in programming. Take up more real life examples and try to write algorithms for them, and keep practising till the time writing algorithms becomes second nature to you.
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