#define _GNU_SOURCE

#include <stdio.h>
#include <unistd.h>
#include <sys/wait.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <signal.h>

#define WHITESPACE " \t\n"    // We want to split our command line up into tokens
// so we need to define what delimits our tokens.
// In this case white space
// will separate the tokens on our command line

#define MAX_COMMAND_SIZE 255 // The maximum command-line size

#define MAX_NUM_ARGUMENTS 10 // Mav shell only supports five arguments

#define MAX_PID_COUNT 15       // The maximum child process pid history size

#define MAX_HISTORY_COUNT 50 // The maximum command history to store

#define MAX_BATCH_COMMANDS 10 // The maximum batch commands to run one by one

#define BATCH_SEP ";"          // Batch commands separator delimiter

// execute is the method which will take one
// command at a time and execute it.
// Declaring prototype of the method.
int execute(char *, char *[], unsigned int *);

// This will hold the process id of last executed child.
pid_t child_pid;

// This method keeps count of history commands.
int count = 0;

// This flag keeps track if process is suspended or not.
int is_suspended = 0;

// This flag keeps track if process is running or not.
int is_running = 0;

// This method handles the ctrl+z signal.
void ctrlzHandler(int sig)
{
signal(SIGTSTP, ctrlzHandler);
//kill(child_pid, SIGSTOP);
if(is_suspended == 0)
{
   fflush(stdout);
   is_suspended = 1;
}
else if(is_suspended == 1)
{
   fflush(stdout);
   is_suspended = 0;
}
printf("\n");

}

// This method handles the ctrl+c signal.
void ctrlcHandler(int sig)
{
//signal(SIGKILL, ctrlzHandler);
if(is_suspended == 1)
{
   fflush(stdout);
   is_suspended = 0;
   //signal(SIGINT, ctrlcHandler);
   kill(child_pid, SIGKILL);
}
}

// This method adds the current command
// to the history array. If history array is
// full it will shift previous history commands
// by one and adds the new command at the end of the array.
void addToHistory(char *hist[], char *command, int count)
{
if (count >= MAX_HISTORY_COUNT)
{
int i = 0;
for (i = 0; i < MAX_HISTORY_COUNT - 1; i++)
{
   hist[i] = strdup(hist[i + 1]);
}
hist[i] = strdup(command);
}
else
{
hist[count] = strdup(command);
}
}

// This method removes the trailing new line
// from the string.
char* removeTrailingNewLine(char *str)
{
int len = strlen(str);
int i = len - 1;
int count = 0;
while (str != NULL && str[i] == '\n')
{
count++;
i--;
}

i = 0;
while (count > 0)
{
str[len - i - 1] = '\0';
i++;
count--;
}
return

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