Dhaka Power Distribution Company (DPDC)
Post: Junior Assistant Manager
Exam Date: 27.06.2025, Exam Taker: BUET
1. Write a C/JAVA program to determine if a given year is a leap year or not.
#include <stdio.h>
int main() {
int year;
printf("Enter a year: ");
scanf("%d", &year);
if ((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0)) {
printf("%d is a leap year.\n", year);
} else {
printf("%d is not a leap year.\n", year);
}
return 0;
}
2. What is the difference between Supervised and Unsupervised learning?
3. Write down the difference between informed and uninformed search algorithm.
4. Given IP address 10.10.0.0/16, you have divided the network into eight equal subnets. Find the subnet mask in dotted decimal and CIDR notation. Also find the first and last usable IP address of the third subnet.
5. Analyze the following C function and determine its Big O Time Complexity and Space Complexity. Explain your reasoning.
#include <stdio.h>
void findDuplicates(int arr[], int n) {
// Outer loop to pick an element
for (int i = 0; i < n; i++) {
// Inner loop to compare it with the rest of the elements
for (int j = i + 1; j < n; j++) {
if (arr[i] == arr[j]) {
printf("Duplicate found: %d\n", arr[i]);
}
}
}
}
#include <stdio.h>
void findDuplicates(int arr[], int n) {
// Outer loop to pick an element
for (int i = 0; i < n; i++) {
// Inner loop to compare it with the rest of the elements
for (int j = i + 1; j < n; j++) {
if (arr[i] == arr[j]) {
printf("Duplicate found: %d\n", arr[i]);
}
}
}
}
6. Explain Different types of Cyber-attack.
7. A communication channel has a signal power of Ps=50mW and a noise power of Pn = 5 mW.
a) Find the signal to noise ratio in linear form and decibels (dB)
b) If the bandwidth of the channel is B = 3 MHz , calculate the channel capacity using Shannon's formula
a) Find the signal to noise ratio in linear form and decibels (dB)
b) If the bandwidth of the channel is B = 3 MHz , calculate the channel capacity using Shannon's formula
Given:
Signal Power (Ps) = 50 mW
Noise Power (Pn) = 5 mW
Bandwidth (B) = 3 MHz = 3 × 106 Hz
(a) Signal to Noise Ratio (SNR)
- SNR (linear) = Ps / Pn
- SNR = 50 / 5 = 10
- SNR (dB) = 10 log10(SNR)
- = 10 log10(10)
- = 10 × 1 = 10 dB
(b) Channel Capacity using Shannon’s Formula
Shannon Capacity Formula:
C = B log2(1 + SNR)
- C = 3 × 106 × log2(1 + 10)
- = 3 × 106 × log2(11)
- log2(11) ≈ 3.46
- C ≈ 3 × 106 × 3.46
- C ≈ 10.38 Mbps
Final Answer:
SNR (linear) = 10
SNR (dB) = 10 dB
Channel Capacity ≈ 10.38 Mbps
