Examples of Algorithms

EXAMPLE 3
Write an algorithm and draw a flowchart that will read the two sides of a rectangle and calculate its area.
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EXAMPLE 4
•Write an algorithm and draw a flowchart that will calculate the roots of a
quadratic equation.
• Hint: d = sqrt ( ), and the roots are: x1 = (–b + d)/2a
and x2 = (–b – d)/2a
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DECISION STRUCTURES
•The expression A>B is a logical expression
•it describes a condition we want to test
•if A>B is true (if A is greater than B) we take the action on left
•print the value of A
•if A>B is false (if A is not greater than B) we take the action on right
•print the value of B
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IF–THEN–ELSE STRUCTURE
•The structure is as follows
If condition then
true alternative
else
false alternative
endif
•The algorithm for the flowchart is as follows:
If A>B then
print A
else
print B
endif
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RELATIONAL OPERATORS
EXAMPLE 5
•Write an algorithm that reads two values, determines the largest value and prints the largest value with an identifying message.
ALGORITHM
Step 1: InputVALUE1, VALUE2
Step 2: if (VALUE1 > VALUE2) then
else
endif
Step 3: Print “The largest value is”, MAX
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NESTED IFS
•One of the alternatives within an IF–THEN–ELSE statement
•may involve furtherIF–THEN–ELSE statement
EXAMPLE 6
•Write an algorithm that reads threenumbers and prints the value of the largest number.
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Exercise:
•Flowchart: Draw the flowchart of the above Algorithm.