Algorithm & Key features / Characteristics of an Algorithm

Algorithm

• The sequence of steps to be performed in order to solve a problem by the computer is known as an algorithm.
• An algorithm may be defined as a finite sequence of steps each of which is precise, unambiguous and executable in finite time.
• Algorithm is a step-by-step procedure, which defines a set of instructions to be executed in a certain order to get the desired output.

1. Input :> There are zero or more quantities which are externally supplied.
2. Output :> At least one quantity is produced.
3. Definiteness :> Each instruction must be clear and unambiguous.
4. Finiteness :> If we trace out the instructions of an algorithm, then for all cases the algorithm will terminate after a finite number of steps.
5. Effectiveness: Every instruction must be sufficiently basic that it can in principle be carried out by a person using only pencil and paper.

 

Key features / Characteristics of an Algorithm

Not all procedures can be called an algorithm. An algorithm should have the following characteristics −

• Unambiguous − Algorithm should be clear and unambiguous. Each of its steps (or phases), and their inputs/outputs should be clear and must lead to only one meaning.
• Input − An algorithm should have 0 or more well-defined inputs.
• Output − An algorithm should have 1 or more well-defined outputs, and should match the desired output.
• Finiteness − Algorithms must terminate after a finite number of steps.
• Feasibility − Should be feasible with the available resources.
• Independent − An algorithm should have step-by-step directions, which should be independent of any programming code.

Example:

1. Write an algorithm to convert the temperature in centigrade to the temperature in Fahrenheit. 

Solution:

Step 1. Read the numeric value of C.

step 2. Calculate F using Formula F= (9/5)*c+32.

Step 3. Write numeric value of F.

Step 4. Stop

2. Write an algorithm to checking whether a number is even or odd.

Solution:

Step 1. Read the given number, say x.

Step 2. Devide x by 2.

Step 3. If the remainder is 1, then print x is odd

Step 4. Otherwise print x is even.

Step 5. Stop.

3. Write an algorithm to find the area of circle.

Solution:

Step 1. Read the value of radius.

Step 2. Calculate area using formula area=3.14*radius*radius.

Step 3. Write the value of area.

Step 4. Stop.