Dinning PhilshrProblem

#include<stdio.h>
#include<conio.h>
char state[10],self[10],spoon[10];
void test(int k)
{
if((state[(k+4)%5]!='e')&&(state[k]=='h')&&(state[(k=1)]!='e'))
{
state[k]='e';
self[k]='s';
spoon[k]='n';
spoon[(k+4)%5]='n';
}
}
void pickup(int i)
{
state[i]='h';
test(i);
if(state[i]=='h')
self[i]='w';
}
void putdown(int i)
{
state[i]='t';
spoon[i]='s';
spoon[i-1]='s';
test((i+4)%5);
test((i+1)%5);
}
main()
{
int ch,a,n,i;
printf("\n Dining Philosopher's Problem:");
printf("\n...........................................\n");
for(i=0;i<5;i++)
{
state[i]='t';
self[i]='s';
spoon[i]='s';
}
printf("\n Initial state of each philososphers:");
printf("\n Phil No : \t Think/Eat \t Status \t\t Spoon");
for(i=0;i<5;i++)
printf("\n %d \t\t %c \t\t %c \t\t %c",i+1,state[i],self[i],spoon[i]);
printf("\n  1.Hungry \n 2.Thinking\n3.Exit");     
printf("\n Enter your choice :");
scanf("%d",&ch);
while(1)
{
switch(ch)
{
case 3:
return 0;
case 1: 
printf("\n Enter wchich philosophers is Hungry :");
scanf("%d",&n);
pickup(n-1);
break;
case 2: 
printf("\n Enter which Philosopher is Thinking :");
scanf("%d",n);
putdown(n-1);
break;
}
printf("\n State of each Philosepher :");
printf("\n Phil no: \t Think/Eat \t Status \t\t Spoon");
for(i=0;i<5;i++)
printf("\n %d \t\t %c \t\t %c \t\t %c",i+1,state[i],self[i],spoon[i]);
printf("\n Exit \n 2.Hungry \n 3. Thinking");
scanf("%d",&ch);
}
} 

Disk Sheduling

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

void fcfs(int noq, int qu[10], int st)
{
 int i,s=0;
 for(i=0;i<noq;i++)
 {
  s+=abs(st-qu[i]);
  st=qu[i];
  }
 printf("\n Total seek time :%d",s);
}

void sstf(int noq, int qu[10], int st, int visit[10])
{
 int min,s=0,p,i;
 while(1)
{
  min=999;
  for(i=0;i<noq;i++)
   if (visit[i] == 0)
    {
      if(min > abs(st - qu[i]))
       {
        min = abs(st-qu[i]);
        p = i;
        }
      }
 if(min == 999)
  break;
  visit[p]=1;
  s=s + min;
  st = qu[p];
  }
 printf("\n Total seek time is: %d",s);
 }

void scan(int noq, int qu[10], int st, int ch)
{
 int i,j,s=0;
 for(i=0;i<noq;i++)
 {
  if(st < qu[i])
  {
   for(j=i-1; j>= 0;j--)
   {
    s=s+abs(st - qu[j]);
    st = qu[j];
    }
   if(ch == 3)
   {
   s = s + abs(st - 0);
   st = 0;
   }
  for(j = 1;j < noq;j++)
  {
   s= s + abs(st - qu[j]);
   st = qu[j];
   }
  break;
 }
}
printf("\n Total seek time : %d",s);
}

int main()
{
 int n,qu[20],st,i,j,t,noq,ch,visit[20];
 printf("\n Enter the maximum number of cylinders : ");
 scanf("%d",&n);
 printf("enter number of queue elements");
 scanf("%d",&noq);
 printf("\n Enter the work queue");
 for(i=0;i<noq;i++)
 {
  scanf("%d",&qu[i]);
  visit[i] = 0;
  }
 printf("\n Enter the disk head starting posision: \n");
 scanf("%d",&st);
 while(1)
 {
  printf("\n\n\t\t MENU \n");
  printf("\n\n\t\t 1. FCFS \n");
  printf("\n\n\t\t 2. SSTF \n");
  printf("\n\n\t\t 3. SCAN \n");
  printf("\n\n\t\t 4. EXIT \n");
  printf("\nEnter your choice: ");
  scanf("%d",&ch);
  if(ch > 2)
   {
   for(i=0;i<noq;i++)
   for(j=i+1;j<noq;j++)
   if(qu[i]>qu[j])
   {
    t=qu[i];
    qu[i] = qu[j];
    qu[j] = t;
    }
   }
   switch(ch)
    {
    case 1: printf("\n FCFS \n");
            printf("\n*****\n");
            fcfs(noq,qu,st);
            break;

    case 2: printf("\n SSTF \n");
            printf("\n*****\n");
            sstf(noq,qu,st,visit);
            break;
    case 3: printf("\n SCAN \n");
            printf("\n*****\n");
            scan(noq,qu,st,ch);
            break;
    case 4: 
         exit(0);
 }
 }
 return 0;
 getch();
}

Encryption-DecptnInGraph

#include<stdio.h>
#include<conio.h>
#include<math.h>
int main(){
    int a[8][8],b[8][8],n,t;
    printf("\n\tEnter number of vertices(where n>=3 & n is odd number ):\t");
    scanf("%d",&n);
    printf("\n\tYou can send %d messages by this graph:\t ",(n-1)/2);
    printf("\n\tEnter values of adjacency matrix :\n");
    printf("\t\n");
      printf("\nEnter the time when receiver receives the all messages:\t ");
    scanf("%d",&t);
    for(int i=0;i<n;i++){
            printf("\t");
          for(int j=0;j<n;j++){
                   printf("\t");
                    scanf("%d",&a[i][j]);
                   
                     printf("\t");
                                }
                               
                                printf("\n");
                               
                    }
   printf("\n\tEntered Matrix is:");
    for(int i=0;i<n;i++){
            printf("\n");
            for(int j=0;j<n;j++){
                    printf("%d",a[i][j]);
                    printf("\t");
                    }
                    }           
 printf("\nReceiver receives all the messages at \t t=%d ",t);
 for(int l=t-1;l>=0;l--){
   printf("\n\n New Decrypted data at t=%d:\n\n",l);
    for(int i=0;i<n;i++){
              printf("\n");
            for(int j=0;j<n;j++){
                   b[i][j]= ((a[i][j])-1)/(2*(l+1));
                   a[i][j]=b[i][j];
                   printf("%d",a[i][j]);
                   printf("\t");
                        }
                                 }
                               
              } 
              return 0;
              getch();  
              }

Producer consumer problem

#include<stdio.h>
#include<pthread.h>
#include<semaphore.h>
int buf[5],f,r;
sem_t mutex,full,empty;
void *produce(void *arg)
{
    int i;
    for(i=0;i<10;i++)
    {
        sem_wait(&empty);
        sem_wait(&mutex);
        printf("produced item is %d\n",i);
        buf[(++r)%5]=i;
        sleep(1);
        sem_post(&mutex);
                sem_post(&full);
        printf("full %u\n",full);
    }
}
void *consume(void *arg)
{
        int item,i;
        for(i=0;i<10;i++)
        {
                sem_wait(&full);
        printf("full %u\n",full);
                sem_wait(&mutex);
                item=buf[(++f)%5];
                printf("consumed item is %d\n",item);
                sleep(1);
                sem_post(&mutex);
                sem_post(&empty);
        }
}
main()
{
    pthread_t tid1,tid2;
    sem_init(&mutex,0,1);
    sem_init(&full,0,1);
    sem_init(&empty,0,5);
    pthread_create(&tid1,NULL,produce,NULL);
        pthread_create(&tid2,NULL,consume,NULL);
    pthread_join(tid1,NULL);
    pthread_join(tid2,NULL);
}