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Step 6: Cut the sandwich into halves or quarters if desired.
Step 7: Serve on a plate.
Step 8: Stop
Algorithm 2: Write an algorithm for crossing the road safely.
Step 1: Start
Step 2: Walk to the zebra crossing or pedestrian signal.
Step 3: Look left, then right, and then left again for vehicles.
Step 4: Wait for the road to be clear or the signal to turn green.
Step 5: Cross the road quickly but carefully.
Step 6: Reach the other side safely.
Step 7: Stop
CONTROL STRUCTURES IN AN ALGORITHM
Control structure is defined as an order of execution of a statement in an algorithm. There are three
types of control structures: sequential, selection, and repetition. Let us explore them in detail.
Sequential
This is the simplest form of control structure, where instructions are executed in a sequential
order, one after the other. For example, steps for calculating the percentage of any student:
1. Input marks for English, Hindi, and Maths.
2. Total the marks.
3. Calculate the percentage.
4. Display the percentage.
Let us write some algorithms based on sequential control structure.
Algorithm 3: Write an algorithm to subtract two numbers and display the result.
Step 1: Start
Step 2: Input num1 and num2.
Step 3: Calculate Sub = num1 – num2.
Step 4: Display Sub.
Step 5: Stop
Algorithm 4: Write an algorithm to calculate the area of a rectangle and display it.
Step 1: Start
Step 2: Input length and width.
Step 3: Calculate area = length * width
Step 4: Display area.
Step 5: Stop
Algorithm 5: Write an algorithm to convert length from meters to kilometers and display it.
Step 1: Start
Step 2: Input temp in Fahrenheit.
40 Information Technology (V5.0)-VII

