// 8. Write a C program to find the largest element in an array using a for loop:

#include <stdio.h>

int main() {
    int size;
    printf("Enter the size of the array: ");
    scanf("%d", &size);

    int arr[size];
    printf("Enter %d elements for the array: ", size);
    for (int i = 0; i < size; i++) {
        scanf("%d", &arr[i]);
    }

    int max = arr[0];

    for (int i = 1; i < size; i++) {
        if (arr[i] > max) {
            max = arr[i];
        }
    }

    printf("Largest element in the array: %d", max);
    return 0;
}

// 9. Write a C program to find the smallest element in an array using a for loop:

#include <stdio.h>

int main() {
    int size;
    printf("Enter the size of the array: ");
    scanf("%d", &size);

    int arr[size];
    printf("Enter %d elements for the array: ", size);
    for (int i = 0; i < size; i++) {
        scanf("%d", &arr[i]);
    }

    int min = arr[0];

    for (int i = 1; i < size; i++) {
        if (arr[i] < min) {
            min = arr[i];
        }
    }

    printf("Smallest element in the array: %d", min);
    return 0;
}

// 10. Write a C program to reverse an array using a for loop:

#include <stdio.h>

int main() {
    int size;
    printf("Enter the size of the array: ");
    scanf("%d", &size);

    int arr[size];
    printf("Enter %d elements for the array: ", size);
    for (int i = 0; i < size; i++) {
        scanf("%d", &arr[i]);
    }

    printf("Original array: ");
    for (int i = 0; i < size; i++) {
        printf("%d ", arr[i]);
    }

    printf("\nReversed array: ");
    for (int i = size - 1; i >= 0; i--) {
        printf("%d ", arr[i]);
    }

    return 0;
}

// 11. Write a C program to sort an array in ascending order using a for loop:

#include <stdio.h>

int main() {
    int size;
    printf("Enter the size of the array: ");
    scanf("%d", &size);

    int arr[size];
    printf("Enter %d elements for the array: ", size);
    for (int i = 0; i < size; i++) {
        scanf("%d", &arr[i]);
    }

    // Sorting logic (bubble sort)
    for (int i = 0; i < size - 1; i++) {
        for (int j = 0; j < size - i - 1; j++) {
            if (arr[j] > arr[j + 1]) {
                int temp = arr[j];
                arr[j] = arr[j + 1];
                arr[j + 1] = temp;
            }
        }
    }

    printf("Array in ascending order: ");
    for (int i = 0; i < size; i++) {
        printf("%d ", arr[i]);
    }

    return 0;
}

// 12. Write a C program to sort an array in descending order using a for loop:

#include <stdio.h>

int main() {
    int size;
    printf("Enter the size of the array: ");
    scanf("%d", &size);

    int arr[size];
    printf("Enter %d elements for the array: ", size);
    for (int i = 0; i < size; i++) {
        scanf("%d", &arr[i]);
    }

    // Sorting logic (bubble sort)
    for (int i = 0; i < size - 1; i++) {
        for (int j = 0; j < size - i - 1; j++) {
            if (arr[j] < arr[j + 1]) {
                int temp = arr[j];
                arr[j] = arr[j + 1];
                arr[j + 1] = temp;
            }
        }
    }

    printf("Array in descending order: ");
    for (int i = 0; i < size; i++) {
        printf("%d ", arr[i]);
    }

    return 0;
}

// 13. Write a C program to find the sum of the digits of a given number using a while loop:

#include <stdio.h>

int main() {
    int number, sum = 0;
    printf("Enter a number: ");
    scanf("%d", &number);

    while (number != 0) {
        sum += number % 10;
        number /= 10;
    }

    printf("Sum of digits: %d", sum);
    return 0;
}

// 14. Write a C program to check if a given number is a palindrome or not using a while loop:

#include <stdio.h>

int main() {
    int number, reversedNumber = 0, originalNumber, remainder;
    printf("Enter a number: ");
    scanf("%d", &number);

    originalNumber = number;

    while (number != 0) {
        remainder = number % 10;
        reversedNumber = reversedNumber * 10 + remainder;
        number /= 10;
    }

    if (originalNumber == reversedNumber) {
        printf("%d is a palindrome.", originalNumber);
    } else {
        printf("%d is not a palindrome.", originalNumber);
    }

    return 0;
}

// 15. Write a C program to convert a decimal number to binary using a while loop:

#include <stdio.h>

int main() {
    int decimalNumber, remainder, binaryNumber = 0, base = 1;
    printf("Enter a decimal number: ");
    scanf("%d", &decimalNumber);

    while (decimalNumber > 0) {
        remainder = decimalNumber % 2;
        binaryNumber += remainder * base;
        decimalNumber /= 2;
        base *= 10;
    }

    printf("Binary equivalent: %d", binaryNumber);
    return 0;
}

// 16. Write a C program to convert a binary number to decimal using a while loop:

#include <stdio.h>

int main() {
    int binaryNumber, decimalNumber = 0, base = 1, remainder;
    printf("Enter a binary number: ");
    scanf("%d", &binaryNumber);

    while (binaryNumber > 0) {
        remainder = binaryNumber % 10;
        decimalNumber += remainder * base;
        binaryNumber /= 10;
        base *= 2;
    }

    printf("Decimal equivalent: %d", decimalNumber);
    return 0;
}

// 17. Write a C program to find the GCD of two numbers using a while loop:

#include <stdio.h>

int main() {
    int num1, num2;
    printf("Enter two numbers: ");
    scanf("%d %d", &num1, &num2);

    while (num1 != num2) {
        if (num1 > num2) {
            num1 -= num2;
        } else {
            num2 -= num1;
        }
    }

    printf("GCD: %d", num1); // or num2, since they're equal now
    return 0;
}

// 18. Write a C program to find the LCM of two numbers using a while loop:

#include <stdio.h>

int main() {
    int num1, num2, max;
    printf("Enter two numbers: ");
    scanf("%d %d", &num1, &num2);

    max = (num1 > num2) ? num1 : num2;

    while (1) {
        if (max % num1 == 0 && max % num2 == 0) {
            printf("LCM: %d", max);
            break;
        }
        max++;
    }

    return 0;
}

// 19. Write a C program to print all Armstrong numbers between 1 and 1000 using a for loop:

#include <stdio.h>
#include <math.h>

int main() {
    int num, originalNum, remainder, result = 0, n = 0;
    printf("Armstrong numbers between 1 and 1000: ");

    for (num = 1; num <= 1000; num++) {
        originalNum = num;

        while (originalNum != 0) {
            originalNum /= 10;
            ++n;
        }

        originalNum = num;

        while (originalNum != 0) {
            remainder = originalNum % 10;
            result += pow(remainder, n);
            originalNum /= 10;
        }

        if (result == num) {
            printf("%d ", num);
        }

        n = 0;
        result = 0;
    }

    return 0;
}

// 20. Write a C program to print all perfect numbers between 1 and 1000 using a for loop:

#include <stdio.h>

int main() {
    int i, num, sum;

    printf("Perfect numbers between 1 and 1000: ");

    for (num = 1; num <= 1000; num++) {
        sum = 0;

        for (i = 1; i < num; i++) {
            if (num % i == 0) {
                sum += i;
            }
        }

        if (sum == num) {
            printf("%d ", num);
        }
    }

    return 0;
}

/*
Perfect number vo number hota hai jo apne divisors ke sum ke barabar hota hai

For example 6 ek Perfect number hai

6 ke divisors 1, 2, 3

Agar in divisors ko sum kare to 6 hi aayega

1 + 2 + 3 == 6

*/

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// udp server program

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <netinet/in.h>

#define PORT 8888
#define MAX_BUFFER_SIZE 1024

int main() {
    int sockfd;
    struct sockaddr_in serverAddr, clientAddr;
    socklen_t addrLen = sizeof(clientAddr);
    char buffer[MAX_BUFFER_SIZE];

    // Creating socket file descriptor
    if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
        perror("Socket creation error");
        exit(EXIT_FAILURE);
    }

    memset(&serverAddr, 0, sizeof(serverAddr));
    memset(&clientAddr, 0, sizeof(clientAddr));

    serverAddr.sin_family = AF_INET;
    serverAddr.sin_addr.s_addr = INADDR_ANY;
    serverAddr.sin_port = htons(PORT);

    // Bind the socket to the specified port
    if (bind(sockfd, (const struct sockaddr *)&serverAddr, sizeof(serverAddr)) == -1) {
        perror("Bind error");
        exit(EXIT_FAILURE);
    }

    printf("UDP server running on port %d\n", PORT);

    // Receive data from clients indefinitely
    while (1) {
        int bytesReceived = recvfrom(sockfd, (char *)buffer, MAX_BUFFER_SIZE, 0, (struct sockaddr *)&clientAddr, &addrLen);
        buffer[bytesReceived] = '\0'; // Null-terminate the received data
        printf("Received message from client: %s\n", buffer);
    }

    return 0;
}

// udp client program

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <netinet/in.h>

#define PORT 8888
#define SERVER_IP "127.0.0.1"

int main() {
    int sockfd;
    struct sockaddr_in serverAddr;
    char *message = "Hello, UDP Server!";

    // Creating socket file descriptor
    if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
        perror("Socket creation error");
        exit(EXIT_FAILURE);
    }

    memset(&serverAddr, 0, sizeof(serverAddr));

    serverAddr.sin_family = AF_INET;
    serverAddr.sin_port = htons(PORT);
    serverAddr.sin_addr.s_addr = inet_addr(SERVER_IP);

    // Send a message to the server
    if (sendto(sockfd, (const char *)message, strlen(message), 0, (const struct sockaddr *)&serverAddr, sizeof(serverAddr)) == -1) {
        perror("Sendto error");
        exit(EXIT_FAILURE);
    }

    printf("Message sent to server: %s\n", message);

    close(sockfd);

    return 0;
}

/*
If you want run udp server and client program here then use 2 telegram id

First run udp server program from 1st id
Then run udp client program from second id
Otherwise it will give error
*/

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