#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
}

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

int glbvar = 6;
int main() {
  int locvar = 88;
  pid_t pid;
  printf("Before fork()\n");
  if ((pid = fork()) == 0) {
    /* child */
    glbvar++;
    locvar++;
  } else if (pid > 0) {
    /* parent */
    sleep(2);
  } else
    perror("fork error");
  printf("pid=%d, glbvar=%d, locvar=%d\n", getpid(), glbvar, locvar);
  return 0;
} /* end main */

// compile: gcc socketTCPServer.c -o socketTCPServer.out
// usage  : ./socketTCPServer.out port
// Server

#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>

int main(int argc, char *argv[]){
        int listenfd = 0, connfd = 0, cli_size, portno;

        struct sockaddr_in serv_addr, cli_addr;

        char sendBuff[1025];

        if((listenfd = socket(AF_INET, SOCK_STREAM, 0)) == -1){
                printf("socket error\n");
                exit(EXIT_FAILURE);
        }

        memset(&serv_addr, '0', sizeof(serv_addr));
        memset(sendBuff, '0', sizeof(sendBuff));

        serv_addr.sin_family = AF_INET;
        serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
        portno = atoi(argv[1]);
        serv_addr.sin_port = htons(portno);

        const int on = 1;
        setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));

        if(bind(listenfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr)) == -1){
                printf("bind error\n");
                exit(EXIT_FAILURE);
        }


        if(listen(listenfd, 5) == -1){
                printf("listen error\n");
                exit(EXIT_FAILURE);
        }

        while(1){
                cli_size = sizeof(cli_addr);
                if((connfd = accept(listenfd, (struct sockaddr*)&cli_addr, &cli_size)) == -1){
                        printf("accept error\n");
                        exit(EXIT_FAILURE);
                }

                strcpy(sendBuff, "Server Message: SUCCESS\n");
                write(connfd, sendBuff, strlen(sendBuff));

                close(connfd);
                sleep(1);
        }
        return 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;
}

//===============replaceString.c===============
#include "replaceString.h"

//Normally I'd make a replaceStringMalloc to return a malloced string or a replaceStringMut to change the original string, but I'm not satisfied with those function names so it's best just to do to = (char*)malloc(replaceStringLength(from, replace, replacement)); replaceString(to, from, replace, replacement);
//If this was c++, I'd have no problem just overloading replaceString
//Returns the length of the resulting string (minus the null char)
size_t replaceStringLength(const char* from, const char* replace, const char* replacement){
	size_t fromLength = strlen(from);
	size_t replaceLength = strlen(replace);
	size_t replacementLength = strlen(replacement);
	size_t fromEndIt = 0;
	size_t toLength = 0;
	while(fromEndIt < fromLength){
	int replaceIt = 0;
	while(replaceIt < replaceLength && (fromEndIt+replaceIt) < fromLength && from[fromEndIt + replaceIt] == replace[replaceIt]){
	++replaceIt;
	}
	if(replaceIt == replaceLength){
	//Update from buffer iterator positions
	toLength += (fromEndIt + replacementLength);
	from += (fromEndIt + replaceLength);
	fromEndIt = 0;
	continue;
	}
	++fromEndIt;
	}
	toLength += fromEndIt;
	return toLength;
}
//Baller replaceString by Leif Messinger
//Needs null terminated from, replace, and replacement strings as well as a large block of memory to store the result.
void replaceString(char* to, const char* from, const char* replace, const char* replacement){
	size_t fromLength = strlen(from);
	size_t replaceLength = strlen(replace);
	size_t replacementLength = strlen(replacement);
	size_t fromEndIt = 0;
	while(fromEndIt < fromLength){
	int replaceIt = 0;
	while(replaceIt < replaceLength && (fromEndIt+replaceIt) < fromLength && from[fromEndIt + replaceIt] == replace[replaceIt]){
	++replaceIt;
	}
	if(replaceIt == replaceLength){
	//Copy the string before the matched bit
	memcpyToAndShiftPointers(to, from, fromEndIt);
	//Copy the replacement too
	memcpyToAndShiftPointer(to, replacement, replacementLength);
	//Update from buffer iterator positions
	from += replaceLength;
	fromEndIt = 0;
	continue; //I don't want this thing to get incremented again
	}
	++fromEndIt;
	}
	//Copy the rest of the unmatched string
	memcpyToAndShiftPointer(to, from, fromEndIt);
	to[0] = '\0'; //Should work
}
//===============replaceString.h===============
#ifndef REPLACE_STRING_H
#define REPLACE_STRING_H
#include <string.h>

#define memcpyToAndShiftPointer(to,from,n); memcpy((to),(from),(n)); (to) += (n);
#define memcpyToAndShiftPointers(to,from,n); memcpy((to),(from),(n)); (to) += (n); (from) += n;

//Normally I'd make a replaceStringMalloc to return a malloced string or a replaceStringMut to change the original string, but I'm not satisfied with those function names so it's best just to do to = (char*)malloc(replaceStringLength(from, replace, replacement)); replaceString(to, from, replace, replacement);
//If this was c++, I'd have no problem just overloading replaceString
//Returns the length of the resulting string (minus the null char)
size_t replaceStringLength(const char* from, const char* replace, const char* replacement);
//Baller replaceString by Leif Messinger
//Needs null terminated from, replace, and replacement strings as well as a large block of memory to store the result.
void replaceString(char* to, const char* from, const char* replace, const char* replacement);
#endif
//===============replaceStringMain.c===============
#include <stdio.h>
#include <stdlib.h>
#include "replaceString.h"

#define BUFFER_SIZE (1<<21) //About a mebibyte
//There could be matches between buffers, so make sure the buffer size you set it to is good enough for your application. Basically as big as your input.

//Replaces strings from sdtin, then outputs it to stdout
//./a.out [[replace], [replacement]]...
int main(int argc, char** argv){
	char* buffer1 = (char*) malloc(BUFFER_SIZE);
	char* buffer2 = (char*) malloc(BUFFER_SIZE);
	if(buffer1 == NULL || buffer2 == NULL){
	perror("You need a couple MBs of ram my boy");
	return 1;
	}
	while(!feof(stdin)){
	fread(buffer1, BUFFER_SIZE, 1, stdin);
	char* activeBuffer = buffer1;
	char* inactiveBuffer = buffer2;
	char* tmp;
	for(size_t i = 1; (i + 1) < argc; i += 2){
	//puts(activeBuffer);
	replaceString(inactiveBuffer, activeBuffer, argv[i], argv[i+1]);
	//Swap buffers
	tmp = activeBuffer;
	activeBuffer = inactiveBuffer;
	inactiveBuffer = tmp;
	}
	fputs(activeBuffer, stdout);
	}
	free(buffer1);
	free(buffer2);
	return 0;
}

// The following code is the fast inverse square root implementation from Quake III Arena
// this code has been stripped of C preprocessor directives, but includes the exact original comment text
float Q_rsqrt( float number )
{
	long i;
	float x2, y;
	const float threehalfs = 1.5F;

	x2 = number * 0.5F;
	y  = number;
	i  = * ( long * ) &y;                       // evil floating point bit level hacking
	i  = 0x5f3759df - ( i >> 1 );               // what the fuck? 
	y  = * ( float * ) &i;
	y  = y * ( threehalfs - ( x2 * y * y ) );   // 1st iteration
//	y  = y * ( threehalfs - ( x2 * y * y ) );   // 2nd iteration, this can be removed

	return y;
}