1) What is the first step in problem-solving? A) Writing code B) Debugging C) Understanding the problem D) Optimizing the solution Answer: C 2) Which of these is not a step in the problem-solving process? A) Algorithm development B) Problem analysis C) Random guessing D) Testing and debugging Answer: C 3) What is an algorithm? A) A high-level programming language B) A step-by-step procedure to solve a problem C) A flowchart D) A data structure Answer: B 4) Which of these is the simplest data structure for representing a sequence of elements? A) Dictionary B) List C) Set D) Tuple Answer: B 5) What does a flowchart represent? A) Errors in a program B) A graphical representation of an algorithm C) The final solution to a problem D) A set of Python modules Answer: B 6) What is pseudocode? A) Code written in Python B) Fake code written for fun C) An informal high-level description of an algorithm D) A tool for testing code Answer: C 7) Which of the following tools is NOT commonly used in pr...
CONTROL STRUCTURES USED IN ALGORITHMS
An algorithm has a finite number of steps. Some steps may involve decision-making and repetition. Broadly speaking, an algorithm may employ one of the following control structures: (a) sequence,
(b) decision, and (c) repetition.
Sequence
By sequence, we mean that each step of an algorithm is executed in a specified order. Let us write an algorithm to
add two numbers. This algorithm performs the steps in a purely sequential order, as shown in below.
Decision
Decision statements are used when the execution of a process depends on the outcome of some condition. For
example, if x = y, then print EQUAL. So the general form of IF construct can be given as:
IF condition Then process
A condition in this context is any statement that may evaluate to either a true value or a false value. In the above example, a variable x can be either equal to y or not equal to y. However, it cannot
be both true and false. If the condition is true, then the process is executed.
A decision statement can also be stated in the following manner:
IF condition
Then process1
ELSE process2
This form is popularly known as the IF–ELSE construct. Here, if the condition is true, then process1 is executed, else process2 is executed. Below fig shows an algorithm to check if two numbers
are equal.
Repetition
Repetition, which involves executing one or more steps for a number of times, can be implemented using constructs such as while, do–while, and for loops. These loops execute one or more steps until some condition is true. Figure below shows an algorithm that prints the first 10 natural numbers
Programming Examples
1. Write an algorithm for swapping two values.
Step 1: Input first number as A
Step 2: Input second number as B
Step 3: SET TEMP = A
Step 4: SET A = B
Step 5: SET B = TEMP
Step 6: PRINT A, B
Step 7: END
2. Write an algorithm to find the larger of two numbers.
Step 1: Input first number as A
Step 2: Input second number as B
Step 3: IF A>B
PRINT A
ELSE
IF A<B
PRINT B
ELSE
PRINT "The numbers are equal"
[END OF IF]
[END OF IF]
Step 4: END
3. Write an algorithm to find whether a number is even or odd.
Step 1: Input number as A
Step 2: IF A%2 =0
PRINT "EVEN"
ELSE
PRINT "ODD"
[END OF IF]
Step 3: END
4. Write an algorithm to print the grade obtained by a student using the following rules.
Step 1: Enter the Marks obtained as M
Step 2: IF M>75
PRINT O
Step 3: IF M>=60 AND M<75
PRINT A
Step 4: IF M>=50 AND M<60
PRINT B
Step 5: IF M>=40 AND M<50
PRINT C
ELSE
PRINT D
Less then 40 D
[END OF IF]
Step 6: END
Marks Grade
Above 75. O
60–75 A
50–59 B
40–49 C
5. Write an algorithm to find the sum of first N natural numbers.
Step 1: Input N
Step 2: SET I = 1, SUM = 0
Step 3: Repeat Step 4 while I <= N
Step 4: SET SUM = SUM + I
SET I = I + 1
[END OF LOOP]
Step 5: PRINT SUM
Step 6: END