AlgorithmBy Taimoor Abdullah Khan

BSCS - 1st

Definition“Set of instructions used to perform a certain task.”

Characteristics of an Algorithm• Well-ordered Collection.• Unambiguous.• Effective.• Computable Operations.• Executable.• Result giving.• Halts in Finite amount of time.

Elements of Algorithm1. Constants.2. Variables.3. Arrays.4. Operators.5. Loops.6. Conditional Statements.7. Comments

1. Constants• Numbers as same as in mathematics.• Helps Structuring

Example: y = 5*ci = i + 1

2. Variables• For Storing Values.• Can be given any name, but given such to

remind of its purpose.Sum, Temp etc.

Value

Variable

3. Arrays• Two or more Variables with same name.• Addressed individually by their index.

myArray[7]• Variable or constant both used to address the index.• Each location can store a different value.• Usually Starting at index 0.

myA

rray

0 myA

rray

1 myA

rray

2

ValueValueValue

4. Operators• Used to perform Operations on Variables or

Constants.• Mathematical Operators: +, -, *, / and %.• Assignment Operator: =• Comparison Operator: ==• Increment , Decrement Operator: ++, --

5. Iteration• Used to repeat a certain code or lines.• Useful for replacing repetition.• Can use Index variables for Arrays.• Major two types of loops: for loop

While loop• Can be stopped from inside off loop body by using

break; statement.

While Loop• Repeats if a certain Condition is true.• Stops when Condition becomes false.• Can repeat Infinite times.• Can be given value ‘1’ to represent Boolean value for ‘True’ so the loop remains

true.

• Syntax: while(Condition) { Loop body; }

For Loop• Given a Variable, for which the condition is set.• Variable is Incremented or Decremented.• Repeats for fixed amount of times.• Syntax: for( i = 0; i <= n; i++) //n is any number

{Loop body;

}

6. Conditional Statement• Used to take decision.• Checks a Condition.• Runs a statement body if Condition is true.• Otherwise runs statment body for “Else” statement if any is given.• Syntax: If(Condition)

{Loop body;

}Else {

Loop body; }

7. Comments• Useful in long and complex programs.• Can be written where required

explanation.• Mostly written after ‘//’.

The EndWhat Are You Staring At?? Its Done!

Thank you.