Algorithms and Flowcharts

1- Algorithms
Algorithms : The term algorithm originally referred to any computation performed via a set of rules applied to numbers written in decimal form. The word is derived from the phonetic pronunciation of the last name of Abu Ja far Mohammed ibn Musa al-Khowarizmi, who was an Arabic mathematician who invented a set of rules for performing the four basic arithmetic operations (addition, subtraction, multiplication and division) on decimal numbers. Thus An algorithm is a representation of a solution to a problem.
Definition:
An algorithm is procedure consisting of a finite set of simple rules which specify a finite sequence of operations that provides the solution to a problem, or to a specific class of problems for any allowable set of input quantities. In other word, an algorithm is a step-by-step procedure to solve a given problem.
Example 1: write the algorithm to find the results of this equation :
S = A+B+C+D
Solution :
1- Start
2- Read A,B,C,D
3- Calculate S =A+B+C+D
4- Print the value of S
5- End.

Example 2: Write an algorithm to determine a student’s final grade and indicate whether it is passing or failing. The final grade is calculated as the average of four marks.
Solution :
1- Start
2- I= I+1
3- Input M
4- S=S+M
5- If I< 4 go to the step 2
6- Av = S / 4
7- If Av below 50 print “pass” , else , print “fail”.
8- End.