PROGRAMMING CONCEPT

Chapter 2 – Programming Concept

Questions and answers

1. Fill in the blanks

(a) Problem-solving techniques are helpful in solving problems.

(b) Flowchart is a process of pictorial illustration for solving a problem.

(c) The input/output in a flowchart is represented by a parallelogram shape.

(d) An operator which is used to assign a value to a variable is called assignment operator.

(e) A sequence of instructions used to solve a particular task is called an algorithm.

(f) An algorithm is a set of instructions.

(g) Assembly language uses mnemonics.

(h) Interpreters convert high-level language to machine language line by line.

(i) The machine language is also known as binary language.

(j) A high-level language is also known as human-like language.

2. State True or False

(a) A flowchart is a step-by-step procedure for calculations.
➡️ False

(b) Constants are the quantities whose values cannot be changed.
➡️ True

(c) Variable is a named space in the computer’s memory whose value can be changed during the execution of a program.
➡️ True

(d) The occurrence of incorrect or unexpected result is called an error.
➡️ True

(e) Relational operators are used to assign values.
➡️ False

(f) Machine language is a 1st generation language.
➡️ True

Here are the complete answers for Questions 3 to 8 from the page.

3. Match Column A with Column B

Column A	Correct Match
Constants	Not Changeable Quantities
Error	Incorrect result
Variables	Changeable quantities
Arithmetic operator	Mod
Relational operator	!=
Assignment operator	Equal to

4. Short Answer Questions

(a) What is a program?

A program is a sequence of instructions written in a programming language to perform a particular task or solve a problem.

(b) Differentiate between a constant and a variable.

Constant	Variable
Its value cannot be changed during program execution.	Its value can be changed during program execution.
Example: `10`	Example: `age = 14`

(c) Differentiate between a Syntax error and Logical error.

Syntax Error: An error caused by breaking the rules of a programming language. The program may not run.

Logical Error: An error in the logic of a program that causes it to produce an incorrect result.

Example:

Syntax: Missing ) or incorrect command.
Logical: Using a - b when the problem requires a + b.

(d) What is a flowchart?

A flowchart is a pictorial representation of the steps of an algorithm using standard symbols and arrows.

(e) What is an algorithm?

An algorithm is a step-by-step set of instructions used to solve a particular problem.

(f) Name the different number systems of a computer.

The four commonly used number systems are:

Binary – Base 2
Decimal – Base 10
Octal – Base 8
Hexadecimal – Base 16

(g) Name the rules for adding Binary Numbers.

Addition	Result
0 + 0	0
0 + 1	1
1 + 0	1
1 + 1	10
1 + 1 + 1	11

Remember: In binary, 1 + 1 = 10, so we write 0 and carry 1.

(h) Name the rules of multiplication of Binary Numbers.

Multiplication	Result
0 × 0	0
0 × 1	0
1 × 0	0
1 × 1	1

5. Add the following

(a)

+ 10000

-------

Answer = 11100₂

(b)

+ 011000

--------

Answer = 1010000₂

(c)

+ 1111

------

Answer = 11010₂

6. Subtract the following

(a)

10101011

- 01010101

----------

Adding the leading zero:

Answer = 01010110₂

(b)

- 0011111

---------

Answer = 1000111₂

7. Multiply the following

(a)

×   011

-------

-------

Answer = 1111₂

(b)

×       1011

------------

+  101010

------------

111001110

Answer = 111001110₂

8. Divide the following

(a) `1111 ÷ 11`

1111₂ ÷ 11₂ = 101₂

Answer = Quotient 101₂, Remainder 0₂

(b) `111111111 ÷ 1011`

Answer:

Quotient = 101110₂
Remainder = 101₂

Check:

1011₂ × 101110₂ + 101₂ = 111111111₂

(c) `10100110111 ÷ 111`

Answer:

Quotient = 10111110₂
Remainder = 101₂

Check:

111₂ × 10111110₂ + 101₂ = 10100110111₂

Absolutely. Here are the complete answers to Questions 9, 10 and 11, written at a Class 8 level.

9. Give detailed answers

(i) Explain different types of errors in programming with examples.

An error is a mistake in a program that prevents it from working correctly or produces an incorrect result.

1. Compilation Error

An error detected by the compiler while converting the program into machine language.

Example:

int a = 10

If the programming language requires a semicolon, the missing ; causes a compilation error.

2. Syntax Error

An error caused by not following the rules or grammar of a programming language.

Example:

if (a > 5

    print(a)

The closing ) is missing.

3. Semantic Error

An error in the meaning of a statement. The statement may be written correctly but does not make proper sense.

Example:

age = age + "five"

A number is being combined with text incorrectly.

4. Type Error

An error caused by using an inappropriate data type.

Example:

num = "Hello"

print(num + 10)

Text and a number cannot be added in this way.

5. Runtime Error

An error that occurs while the program is running.

Example:

10 / 0

Division by zero causes a runtime error.

6. Logical Error

An error in the logic of a program. The program runs but produces the wrong answer.

Example:

To find the sum:

sum = a - b

The program runs, but subtraction has been used instead of addition.

(ii) What is an arithmetic expression? Explain different types of operators with examples.

An arithmetic expression is a combination of numbers, variables and arithmetic operators that produces a numerical result.

Example:

A + B * 2

Types of operators

1. Arithmetic Operators

They are used to perform mathematical calculations.

Operator	Meaning	Example
`+`	Addition	`A + B`
`-`	Subtraction	`A - B`
`*`	Multiplication	`A * B`
`/`	Division	`A / B`
`%`	Modulus (remainder)	`A % B`
`^`	Power/Exponent	`A ^ 2`

2. Relational Operators

They are used to compare two values. The result is generally True or False.

Operator	Meaning	Example
`==`	Equal to	`A == B`
`!=`	Not equal to	`A != B`
`>`	Greater than	`A > B`
`<`	Less than	`A < B`
`>=`	Greater than or equal to	`A >= B`
`<=`	Less than or equal to	`A <= B`

3. Logical Operators

They are used to combine or reverse conditions.

Operator	Meaning	Example
`AND` / `&&`	Both conditions must be true	`A > 5 AND B < 10`
`OR` / `\|\|`	At least one condition is true	`A > 5 OR B < 10`
`NOT` / `!`	Reverses the result	`NOT(A > 5)`

4. Assignment Operator

It is used to assign a value to a variable.

Example:

A = 10

Here, 10 is assigned to variable A.

9(iii). Convert the algebraic expressions into computer expressions

(a) `(AB) + (BC)`

In computer expressions, multiplication must be written using *.

Answer:

(A * B) + (B * C)

(b) `5X - 7Y`

Answer:

5 * X - 7 * Y

(c) `A + B × C3`

The printed expression appears to show C3. If C3 means C³, then:

Answer:

A + B * C ^ 3

(d) `B2 - 4AC`

Assuming B2 means B²:

Answer:

B ^ 2 - 4 * A * C

(e) `XY - (X-Y)`

Answer:

X * Y - (X - Y)

Important: In many programming languages such as Python, ^ is not the power operator; ** is used for power. But the textbook appears to use ^ as its power notation.

10. Find the solution if A = 3, B = 4 and C = 5

(a) `C - A * B - 5`

Substitute the values:

= 5 - 3 * 4 - 5

= 5 - 12 - 5

= -12

Answer = -12

(b) `(A + B) - C ^ 2`

= (3 + 4) - 5²

= 7 - 25

= -18

Answer = -18

(c) `(B + C) / A * 10`

= (4 + 5) / 3 * 10

= 9 / 3 * 10

= 3 * 10

= 30

Answer = 30

(d) `A ^ 2 + B ^ 2 - 2 * A * R`

There is a problem in the textbook/question here: it uses R, but Question 10 gives values only for A, B and C.

So this expression cannot be calculated exactly unless the value of R is provided.

If the book intended the expression to be:

A² + B² - 2AB

then:

= 3² + 4² - 2 * 3 * 4

= 9 + 16 - 24

= 1

Answer, if R was intended to be B = 4: 1

(e) `C mod A * B + C`

= 5 mod 3 * 4 + 5

= 2 * 4 + 5

= 8 + 5

= 13

Answer = 13

11. Draw the flowchart for

Since these are drawing questions, below I have given the exact flowchart sequence. Use the appropriate standard symbols.

(a) Find the addition of three numbers

Flowchart

       ┌─────────┐

       │  START  │

       └────┬────┘

↓

    ╱───────────────╲

   ╱   Input A, B, C  ╲

   ╲─────────────────╱

↓

     ┌──────────────┐

     │ Sum = A+B+C  │

     └──────┬───────┘

↓

    ╱────────────────╲

   ╱    Display Sum   ╲

   ╲──────────────────╱

↓

       ┌─────────┐

       │   END   │

       └─────────┘

Symbols:

Start/End → Terminal
Input/Display → Parallelogram
Addition → Processing box
Arrows → Flow lines

11(b). Find whether a given number is even or odd

Flowchart

       ┌─────────┐

       │  START  │

       └────┬────┘

↓

    ╱────────────╲

   ╱   Input N    ╲

   ╲──────────────╱

↓

      ┌────────────┐

      │ R = N MOD 2│

      └─────┬──────┘

↓

        ◇────────◇

       ╱  R = 0 ?  ╲

       ◇─────┬────◇

          Yes│    │No

             ↓    ↓

    ╱──────────╲  ╱─────────╲

   ╱ Display    ╲╱ Display   ╲

   ╲  "Even"    ╱╲  "Odd"   ╱

    ╲──────────╱  ╲─────────╱

          ↓          ↓

          └────┬─────┘

↓

          ┌─────────┐

          │   END   │

          └─────────┘

Key idea:
If N MOD 2 = 0 → Even
Otherwise → Odd

11(c). Print natural numbers from 1 to 10

This uses a loop/repetition.

Flowchart

       ┌─────────┐

       │  START  │

       └────┬────┘

↓

       ┌────────┐

       │  N = 1 │

       └────┬───┘

↓

        ◇────────◇

       ╱  N ≤ 10 ? ╲

       ◇─────┬────◇

          Yes│    │No

             ↓    ↓

    ╱────────────╲ ┌─────────┐

   ╱   Display N   ╲│   END   │

   ╲────────────────╱└─────────┘

↓

       ┌────────────┐

       │  N = N + 1 │

       └──────┬─────┘

│

              └──────────→ back to

                           N ≤ 10 ?

Output

1  2  3  4  5  6  7  8  9  10

⭐ Final answers for Q10

Question	Answer
10(a)	-12
10(b)	-18
10(c)	30
10(d)	Cannot determine because R is not given
10(e)	13

Note: For 10(d), I would not recommend writing 1 as the definite answer unless your textbook’s intended expression is A² + B² − 2AB; the printed question clearly shows R, while only A, B and C are assigned values.

PROGRAMMING CONCEPT

3. Match Column A with Column B

4. Short Answer Questions

(a) What is a program?

(b) Differentiate between a constant and a variable.

(c) Differentiate between a Syntax error and Logical error.

(d) What is a flowchart?

(e) What is an algorithm?

(f) Name the different number systems of a computer.

(g) Name the rules for adding Binary Numbers.

(h) Name the rules of multiplication of Binary Numbers.

5. Add the following

(a)

(b)

(c)

6. Subtract the following

(a)

(b)

7. Multiply the following

(a)

(b)

8. Divide the following

(a) 1111 ÷ 11

(b) 111111111 ÷ 1011

(c) 10100110111 ÷ 111

9. Give detailed answers

(i) Explain different types of errors in programming with examples.

1. Compilation Error

2. Syntax Error

3. Semantic Error

4. Type Error

5. Runtime Error

6. Logical Error

(ii) What is an arithmetic expression? Explain different types of operators with examples.

Types of operators

1. Arithmetic Operators

2. Relational Operators

3. Logical Operators

4. Assignment Operator

9(iii). Convert the algebraic expressions into computer expressions

(a) (AB) + (BC)

(b) 5X - 7Y

(c) A + B × C3

(d) B2 - 4AC

(e) XY - (X-Y)

10. Find the solution if A = 3, B = 4 and C = 5

(a) C - A * B - 5

(b) (A + B) - C ^ 2

(c) (B + C) / A * 10

(d) A ^ 2 + B ^ 2 - 2 * A * R

(e) C mod A * B + C

11. Draw the flowchart for

(a) Find the addition of three numbers

Flowchart

11(b). Find whether a given number is even or odd

Flowchart

11(c). Print natural numbers from 1 to 10

Flowchart

Output

⭐ Final answers for Q10

(a) `1111 ÷ 11`

(b) `111111111 ÷ 1011`

(c) `10100110111 ÷ 111`

(a) `(AB) + (BC)`

(b) `5X - 7Y`

(c) `A + B × C3`

(d) `B2 - 4AC`

(e) `XY - (X-Y)`

(a) `C - A * B - 5`

(b) `(A + B) - C ^ 2`

(c) `(B + C) / A * 10`

(d) `A ^ 2 + B ^ 2 - 2 * A * R`

(e) `C mod A * B + C`