Program to create histogram using threading in C language

#include
#include
#include

int a[100], size, N;
int min, max;
int grno;
float grsize;
int histo[50];

int start=0;
pthread_mutex_t lock;
pthread_cond_t cond;

void * work()
{
       int i, temp;

       pthread_mutex_lock(&lock);
               if(start==0)
                       pthread_cond_wait(&cond, &lock);   
       pthread_mutex_unlock(&lock);

       for(;;)
       {
               pthread_mutex_lock(&lock);
               i=size-1;
               size--;
               pthread_mutex_unlock(&lock);

               if(size<0)                 {                         pthread_mutex_lock(&lock);                           pthread_cond_wait(&cond, &lock);                         pthread_mutex_unlock(&lock);                 }                  if(i<0)                         break;                  if(min>a[i])
                       min=a[i];
               if(max<0)                         break;                  temp=(float)((a[i]-min))/grsize;                 if(temp >(grno-1))
                       temp= grno-1;
               histo[temp]++;
       }
}

int main()
{
       pthread_t id;
       void * status;           
       int i, nthread;
       int temp1, temp2;

       pthread_mutex_init(&lock,0);
       pthread_cond_init(&cond,0);

       printf("Enter the size of the array :: ");
       scanf("%d",&size);
       N=size;

       printf("\nEnter the %d elements of array\n",N);
       for(i=0;i=0)
               sleep(1);

       grsize=(float)(max-min)/(float)grno;
       size=N;

       pthread_mutex_lock(&lock);
               pthread_cond_broadcast(&cond);
       pthread_mutex_unlock(&lock);
                                         

       while(size>=0)
               sleep(1);

       pthread_join(id,status);

       printf("\nThe histogram is as follows::\n");
       temp1=min;
       temp2=ceil(grsize);

       for(i=0;i %d = %d\n",temp1, temp2,histo[i]);
                       temp1=temp2+1;
                       temp2+=ceil(grsize);
               }
               else
                       printf("For %d and up values = %d ",temp1, histo[i]);
       }

       pthread_mutex_destroy(&lock);                   

       printf("\n");
       return 0;
}                   

OUTPUT:
--------
Enter the size of the array :: 4

Enter the 4 elements of array
1
2
3
4

Enter the total number of groups required in histogram :: 4

Enter the total number of threads :: 3

The histogram isas follows::
For 1 -> 1 = 1
For 2 -> 2 = 1
For 3 -> 3 = 1
For 4 and up values = 1