section b
question three
a) convert the decimal number 185 to its bcd equivalent. 5
b) change the binary number 1011010110 to hexadecimal. 5
c) write a c program that accepts two numbers as input and then computes the sum and display it. 10
question four
a) define what is meant by operating system of a computer. outline any 5 of its functions. 10
b) state with the aid of examples any two different classes of computer software. 4
c) give the meaning of the following:
i. software 2
ii. virus 2
iii. firewall 2
question five
a) with the aid of a diagram give an explanation for the following network topologies: i) ring ii) star iii)bus 12
b) discuss with the aid of a diagram the purpose of the following devices in data communications: i) hub ii) modem 8
question six
a) define the following terms:
i. variable 2
ii. file 2
iii. program 2
iv. array 2
v. constant 2
b) write a c program that calculates n! where n is a number entered at the keyboard and n!=n*(n - 1)*(n - 2)*---*4*3*2*1. 10
question seven
write a c program to copy the contents of one file to another file with a new name. the program should ask the user for the name of the file to copy from and the name of the new file. 20

Question

Accepted Answer

### Question Three #### a) # Explanation: ## Step1: Split decimal digits Split 185 into 1, 8, 5. Each digit is converted to 4 - bit BCD. 1 in BCD is 0001, 8 in BCD is 1000, 5 in BCD is 0101. ## Step2: Combine BCD digits Combine them together: 0001 1000 0101 # Answer: 0001 1000 0101 #### b) # Explanation: ## Step1: Group binary digits Group the binary number 1011010110 into groups of 4 - bits from right to left. Add leading 0s if necessary. We get 0010 1101 0110. ## Step2: Convert each group to hexadecimal 0010 in hexadecimal is 2, 1101 in hexadecimal is D, 0110 in hexadecimal is 6. # Answer: 2D6 #### c) ```c #include int main() { int num1, num2, sum; printf("Enter two numbers: "); scanf("%d %d", &num1, &num2); sum = num1 + num2; printf("The sum is: %d ", sum); return 0; } ``` ### Question Four #### a) # Brief Explanations: An operating system (OS) is a software that manages computer hardware and software resources and provides common services for computer programs. Five functions: Process management (allocates CPU time to processes), Memory management (allocates and de - allocates memory), File management (organizes and controls access to files), Device management (controls input/output devices), User interface (provides a way for users to interact with the computer). # Answer: An operating system is a software that manages computer hardware and software resources and provides common services for computer programs. Five functions are process management, memory management, file management, device management, user interface. #### b) # Brief Explanations: System software: Examples include operating systems (e.g., Windows, Linux) which manage computer resources. Application software: Examples include word - processing software (e.g., Microsoft Word) which is used for specific tasks like document creation. # Answer: System software (e.g., Windows, Linux); Application software (e.g., Microsoft Word) #### c) # Brief Explanations: i. Software: A set of instructions, data or programs used to operate computers and execute specific tasks. ii. Virus: A malicious software program that can replicate itself and spread from one computer to another, often causing damage to data or system functionality. iii. Firewall: A network security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules. # Answer: i. A set of instructions, data or programs used to operate computers and execute specific tasks. ii. A malicious software program that can replicate itself and spread from one computer to another, often causing damage to data or system functionality. iii. A network security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules. ### Question Five #### a) # Brief Explanations: i. Ring topology: In a ring topology, each device is connected to two other devices, forming a closed loop. Data travels around the ring in one direction. If one device fails, it can affect the entire network. ii. Star topology: In a star topology, all devices are connected to a central hub or switch. If one device fails, it does not affect other devices, but if the central hub fails, the whole network goes down. iii. Bus topology: In a bus topology, all devices are connected to a single communication line (the bus). When a device sends data, it is broadcasted to all other devices on the bus. If the bus fails, the whole network is down. Diagrams can be drawn to illustrate these connections. # Answer: i. In a ring topology, each device is connected to two other devices, forming a closed loop. Data travels around the ring in one direction. If one device fails, it can affect the entire network. ii. In a star topology, all devices are connected to a central hub or switch. If one device fails, it does not affect other devices, but if the central hub fails, the whole network goes down. iii. In a bus topology, all devices are connected to a single communication line (the bus). When a device sends data, it is broadcasted to all other devices on the bus. If the bus fails, the whole network is down. #### b) # Brief Explanations: i. Hub: In data communications, a hub is a device that connects multiple devices in a network. It acts as a central connection point and broadcasts data received on one port to all other ports. Diagram: Multiple devices are connected to the hub ports. ii. Modem: A modem is a device that converts digital signals from a computer into analog signals for transmission over a telephone or cable line and vice - versa. Diagram: A computer is connected to a modem which is then connected to the communication line. # Answer: i. A hub is a device that connects multiple devices in a network. It acts as a central connection point and broadcasts data received on one port to all other ports. ii. A modem is a device that converts digital signals from a computer into analog signals for transmission over a telephone or cable line and vice - versa. ### Question Six #### a) # Brief Explanations: i. Variable: A named storage location in a program that can hold a value which can be changed during the execution of the program. ii. File: A named collection of related data that is stored on a storage device. iii. Program: A set of instructions written in a programming language that, when executed, performs a specific task. iv. Array: A data structure that stores a collection of elements of the same data type, accessed by an index. v. Constant: A value that does not change during the execution of a program. # Answer: i. A named storage location in a program that can hold a value which can be changed during the execution of the program. ii. A named collection of related data that is stored on a storage device. iii. A set of instructions written in a programming language that, when executed, performs a specific task. iv. A data structure that stores a collection of elements of the same data type, accessed by an index. v. A value that does not change during the execution of a program. #### b) ```c #include int main() { int n, i; long long fact = 1; printf("Enter a number: "); scanf("%d", &n); for (i = 1; i <= n; i++) { fact = fact * i; } printf("%d! = %lld ", n, fact); return 0; } ``` ### Question Seven ```c #include #include int main() { FILE *source, *destination; char sourceFileName[100], destinationFileName[100]; char ch; printf("Enter the name of the file to copy from: "); scanf("%s", sourceFileName); source = fopen(sourceFileName, "r"); if (source == NULL) { printf("Error opening source file. "); return 1; } printf("Enter the name of the new file: "); scanf("%s", destinationFileName); destination = fopen(destinationFileName, "w"); if (destination == NULL) { printf("Error opening destination file. "); fclose(source); return 1; } while ((ch = fgetc(source)) != EOF) { fputc(ch, destination); } fclose(source); fclose(destination); printf("File copied successfully. "); return 0; } ```

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QUESTION IMAGE

Question

Explanation:

Question Three

a)

Step1: Split decimal digits

Step2: Combine BCD digits

Step1: Group binary digits

Step2: Convert each group to hexadecimal

Answer:

b)