Computer Science BIEK XII Notes: Complete Notes XII BIEK , Computer Science Past Paper Question With Answer((Detailed Answers)

PREPARED BY: SIR ZUBAIR KHAN 

The Textbook of COMPUTER SCIENCE For Class XII – Class 12 – Sindh Textbook Board 

DETAILED QUESTIONS

Q1: Explain all data types in C-Language? 

Ans: In the C programming language, there are several data types available that allow you to define the type of data that a variable can hold. Here's an explanation of the commonly used data types in C:

• int: It is used to represent integer values. The int data type typically uses 4 bytes of memory and can hold whole numbers within a certain range, usually from -2,147,483,648 to 2,147,483,647.
• float: It is used to represent floating-point numbers, which are numbers with a fractional part. The float data type typically uses 4 bytes of memory and can hold single-precision floating-point values.
• double: It is used to represent double-precision floating-point numbers. The double data type typically uses 8 bytes of memory and can hold larger and more precise floating-point values compared to float.
• char: It is used to represent individual characters. The char data type typically uses 1 byte of memory and can store a single character, such as 'a', 'b', or '3'. It can also store special characters like newline ('\n') or null ('\0').
• short: It is used to represent small integers. The short data type typically uses 2 bytes of memory and can hold a smaller range of values compared to int.
• Long: It is used to represent long integers. The long data type typically uses 4 or 8 bytes of memory (depending on the compiler and platform) and can hold a larger range of values compared to int.
• unsigned: It is used to represent positive numbers or zero. When combined with other data types like int, short, or long, it expands the range of non-negative values that can be stored.
• signed: It is used to represent both positive and negative numbers. The signed keyword is often implicit and not explicitly used in variable declarations since it is the default behavior for most data types.
• enum: It is used to define a set of named constants. An enum creates a new data type that can hold a set of integer values, where each value is assigned a unique name (enumeration constant).
• void: It is a special data type that represents the absence of a value. It is often used as a return type for functions that do not return a value or as a placeholder for function parameters that do not accept any arguments.

Q2: What is a function? what are the advantages of using function? 

Ans: In the context of C programming, a function is a named block of code that performs a specific task or a set of related tasks. It is a fundamental concept in C programming and plays a crucial role in code organization and reusability.

Advantages of using functions in C programming include:

• Modularity: Functions allow you to divide a large program into smaller, manageable modules. Each function performs a specific task, making the code easier to understand, maintain, and debug. Modularity promotes code organization and helps in team collaboration by allowing different programmers to work on separate functions independently.

• Code Reusability: Functions facilitate code reuse by allowing you to define a set of instructions once and call them whenever needed. Instead of rewriting the same code in multiple places, you can encapsulate the common functionality in a function and invoke it from different parts of the program. This not only reduces code duplication but also ensures consistency and improves maintainability.

• Abstraction: Functions provide a level of abstraction by hiding the implementation details of a task behind a function name and interface. Other parts of the program can use the function without needing to understand how it is implemented internally. This abstraction simplifies the usage of complex operations and promotes encapsulation, leading to more modular and flexible code.

• Code Readability: Functions help improve code readability and comprehension. By using meaningful function names and properly defining the purpose of each function, you can make your code more self-explanatory and easier to understand. Functions also allow you to break down complex tasks into smaller, manageable subtasks, making the code more structured and readable.

• Code Maintenance: Functions simplify code maintenance and debugging. If a bug or issue is encountered in a specific functionality, you only need to investigate and modify the corresponding function instead of searching through the entire program. This reduces the scope of potential errors and makes debugging and maintenance more efficient.

• Code Testing: Functions enable better code testing and unit testing. You can write test cases specifically for individual functions to ensure their correctness and proper behavior. This modular approach to testing allows for focused and targeted testing, making it easier to identify and fix issues.

Q3: Define the Switch and break statement with an example? 

Ans: In C programming, the switch statement is used to select one of many code blocks to be executed based on the value of a variable or an expression. It provides an alternative to using multiple if statements when there are several possible values to compare against.

Here's the syntax of the switch statement:

switch (expression)

{

    case value1:

        // Code to be executed if expression matches value1

        break;

    case value2:

        // Code to be executed if expression matches value2

        break;

    // more cases...

    default:

        // Code to be executed if expression doesn't match any case

}

The expression is evaluated, and its value is compared against each case label. If there is a match, the corresponding block of code is executed. The break statement is used to exit the switch statement and prevent the execution of subsequent cases.

Here's an example that demonstrates the use of switch and break statements to determine the day of the week based on a given number:

#include <stdio.h>

int main() {

    int day;

    

    printf("Enter a number (1-7): ");

    scanf("%d", &day);

    

    switch (day) {

        case 1:

            printf("Sunday\n");

            break;

        case 2:

            printf("Monday\n");

            break;

        case 3:

            printf("Tuesday\n");

            break;

        case 4:

            printf("Wednesday\n");

            break;

        case 5:

            printf("Thursday\n");

            break;

        case 6:

            printf("Friday\n");

            break;

        case 7:

            printf("Saturday\n");

            break;

        default:

            printf("Invalid input\n");

            break;

    }

    

    return 0;

}

In this example, the user enters a number between 1 and 7, representing the day of the week. The switch statement evaluates the value of the day and executes the corresponding case. If the value doesn't match any case, the default block is executed. The break statement is used after each case to exit the switch statement and prevent the execution of subsequent cases.

Q4: How many types of decision structures are there in 'C'? Define with examples. OR Define else if statement. How it is different from the switch statement?

Ans: C has three major decision-making instructions—the if statement, the if-else statement, and the switch statement.

1. The if Statement

C uses the keyword if to implement the decision control instruction. The general form of if statement looks like this:

//for single statement

if(condition) 

    statement;

  

//for multiple statement

if(condition) 

{ 

    block of statement; 

}

2. The if-else Statement

The if statement by itself will execute a single statement, or a group of statements, when the expression following if evaluates to true. It does nothing when the expression evaluates to false. Can we execute one group of statements if the expression evaluates to true and another group of statements if the expression evaluates to false? Of course! This is what is the purpose of the else statement is demonstrated as

if (expression)

{ 

    block of statement;

}

else

    statement;

3. Switch Statements or Control Statements

The switch statement is a multi-way decision that tests whether an expression matches one of a number of constant integer values, and branches accordingly. The switch statement that allows us to make a decision from the number of choices is called a switch, or more correctly switch-case-default, since these three keywords go together to make up the switch statement.

switch (expression) 

{

    case constant-expression: 

        statement1;

        statement2;

        break;

    case constant-expression: 

        statement;

        break;

    ...

    default: 

        statement;

}

Q5: Define "Nested" for loop with example.

Ans: In C programming, a nested loop refers to a loop structure where one loop is placed inside another loop. This allows for multiple levels of iteration and is commonly used to iterate over two-dimensional arrays or perform complex repetitive tasks. The inner loop is executed completely for each iteration of the outer loop.

Here's an example of a nested loop that prints a pattern of asterisks:

#include <stdio.h>

int main() {

    int rows, columns;

    printf("Enter the number of rows: ");

    scanf("%d", &rows);

    printf("Enter the number of columns: ");

    scanf("%d", &columns);

    for (int i = 0; i < rows; i++) {

        for (int j = 0; j < columns; j++) {

            printf("* ");

        }

        printf("\n");

    }

    return 0;

}

In this example, the user inputs the number of rows and columns for the pattern. The outer loop iterates rows times, while the inner loop iterates columns times for each outer loop iteration. For each iteration of the inner loop, an asterisk is printed, forming a pattern of asterisks in a rectangular shape.

For instance, if the user enters 4 for rows and 6 for columns, the output will be:

markdown

* * * * * * 

* * * * * * 

* * * * * * 

* * * * * * 

Nested loops can be extended to multiple levels, allowing for more complex iteration patterns. However, it's essential to ensure that the nested loops are properly controlled and terminated to avoid infinite looping.

Q6: Define any four objects in MS Access?

Ans: In Microsoft Access, objects are used to organize and manipulate data within a database. Here are four commonly used objects in MS Access:

• Tables: Tables are the fundamental objects in MS Access that store data in a structured manner. They consist of rows (records) and columns (fields) and represent the data entities within a database. Tables hold the actual data and provide the foundation for other objects.

• Queries: Queries in MS Access are used to retrieve, manipulate, and analyze data from one or more tables. They allow you to define custom search criteria, perform calculations, create relationships between tables, and generate new result sets based on the specified criteria.

• Forms: Forms are graphical user interfaces that provide an interactive way to input, view, and modify data in MS Access. They are used to create user-friendly data entry screens and enable data validation, form navigation, and control interactions with the database. Forms enhance the user experience and provide a convenient way to interact with the data.

• Reports: Reports in MS Access allow you to create formatted and printable documents that present data from tables or queries. Reports enable you to generate professional-looking documents such as invoices, sales reports, or summaries. They provide tools for organizing, grouping, sorting, and summarizing data in a visually appealing format.

Q7: What are the input/output statements in the C programming language? Define any three with examples?

Ans: