#include <stdio.h>
#include <stdlib.h>
int main(){

  int * int_ptr;
  int_ptr = (int *)malloc(2*sizeof(int));
  
  if(!int_ptr) {
    printf("Something went wrong while allocating memory. Exiting...");
    exit(1);
  }
  
  printf("Enter first integer: ");
  scanf("%i", &int_ptr[0]);
  
  printf("Enter second integer: ");
  scanf("%i", &int_ptr[1]);
  
  printf("Original values: 1st = %i 2nd = %i\n",int_ptr[0], int_ptr[1]);
  
  int_ptr[0] = int_ptr[0] ^ int_ptr[1];
  //printf("%i\n", int_ptr[0]);
  int_ptr[1] = int_ptr[0] ^ int_ptr[1];
  //printf("%i\n", int_ptr[1]);
  int_ptr[0] = int_ptr[0] ^ int_ptr[1];
  //printf("%i\n", int_ptr[0]);
  
  printf("Swapped values: 1st = %i 2nd = %i\n", int_ptr[0], int_ptr[1]);

  free(int_ptr);
  exit(0);
}

#include <stdio.h>
#include <stdlib.h>

// give an array of identical coins (ints), represented by 1's and one 2
// we can find the heavy coin (2) by summing the contents of the thirds

int sum_subarr(int arr[], int l, int r){
  int sum = 0;
  for(int i = l; i <= r; i++)
  {
    sum += arr[i];
  }

  return sum;
}

int heavy_coin(int arr[], int l, int r){

  if(r == l)
  {
    return r;
  }
  int midl = l + (r - l)/3;
  int midr = r - (r - l)/3;
  int lw = sum_subarr(arr, l, midl);
  int mw = sum_subarr(arr, midl + 1, midr);

  if ( lw > mw )
  {
    return heavy_coin(arr, l, midl);
  }
  else if ( lw < mw )
  {
    return heavy_coin(arr, midl + 1, midr);
  }
  else
  {
    return heavy_coin(arr, midr + 1, r);
  }

}

int main(int argc, char *argv[])
{

  int arr[] = {1,1,1,1,2,1,1,1,1};
  int l = 0;
  int r = 8;
  int res = -1;

  res = heavy_coin(arr, l, r);

  printf("Hevy coin is at index: %d\n", res);

  return EXIT_SUCCESS;
}

#include <stdio.h>
#include <assert.h>
#include <signal.h>

void myHandler(int iSig) {
  printf("In myHandler with argument %d\n", iSig);
}
int main() {
  void( * pfRet)(int) = signal(SIGINT, myHandler);
  assert(pfRet != SIG_ERR);
  printf("Entering an infinite loop\n");
  while (1) {
    printf(".");
  }
  return 0; // use CTRL+\ to exit
}

// Client side implementation of UDP client-server model
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>

#define PORT 8008
#define MAXLINE 1024

// Driver code
int main() {
        char buffer[MAXLINE];
        struct sockaddr_in servaddr;

        // Creating socket file descriptor

        int sockfd = socket(AF_INET, SOCK_DGRAM, 0);
        if ( sockfd < 0 ) {
                perror("socket creation failed");
                exit(EXIT_FAILURE);
        }

        struct timeval timeout;
        timeout.tv_sec = 1; //Wait 1 second
        timeout.tv_usec = 0;

        if (setsockopt (sockfd, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof timeout) < 0) perror("setsockopt failed\n");

        if (setsockopt (sockfd, SOL_SOCKET, SO_SNDTIMEO, &timeout, sizeof timeout) < 0) perror("setsockopt failed\n");

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

        // Filling server information
        servaddr.sin_family = AF_INET;
        servaddr.sin_port = htons(PORT);
        servaddr.sin_addr.s_addr = inet_addr("192.168.4.65");

        for(int i = 0; i < 10; ++i){
                char* message = "PING";
                int sendStatus = sendto(sockfd, (const char *)message, strlen(message), MSG_CONFIRM, (const struct sockaddr *) &servaddr, sizeof(servaddr));
                if(sendStatus >= 0){
                        printf("Sent PING\n");
                }else{
                        printf("Send failed\n");
                        continue;
                }

                int len = sizeof(struct sockaddr_in);
                int bytesRecieved = recvfrom(sockfd, (char *)buffer, MAXLINE, MSG_WAITALL, (struct sockaddr *) &servaddr, &len); //We can reuse servaddr because the port the server sends messages from is the same one we send to
                if(bytesRecieved >= 0){
                        buffer[bytesRecieved] = '\0';
                        printf("Recieved %s\n", buffer);
                }else{
                        printf("Recieved nothing: Packet Dropped\n", buffer);
                }
        }

        close(sockfd);

        return 0;
}

#include <stdio.h>
#include <stdlib.h>

calculate(a, b)
int a;
int b;
{
        printf("%d", a+b);
}

main(argc, argv)
int argc;
char** argv;
{
        if(argc < 3){
                return 0;
        }
        calculate(atoi(argv[1]), atoi(argv[2]));
}

#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>

int main() {
  pid_t pid; /* could be int */
  int i;
  pid = fork();
  printf("PID=%d\n", pid);
  if (pid > 0) {
    /* parent */
    for (i = 0; i < 10; i++)
      printf("\t\t\tPARENT %d\n", i);
  } else {
    /* child */
    for (i = 0; i < 10; i++)
      printf("CHILD %d\n", i);
  }
  return 0;
}