4.16

4.17

4.18

4.19

4.20

4.21

4.22

4.16

#include <stdio.h>
#include <pthread.h>
#include <stdlib.h>
#include <string.h>
int max_num;
int min_num;
int avg_num;
int num_count;

void *avg_calc(void *ptr)
{
        int sum = 0;
        for(int i = 0 ; i < num_count ; i++)
        {
                sum 
 
+= ((int*)ptr)[i];

        }
        avg_num = sum/num_count;

        pthread_exit(0);
}
void *max_calc(void * ptr)
{
        int max = 0x80000000;
        for(int i=0;i<num_count;i++)
        {
                if(((int*)ptr)[i] > max)
                {
                        max = ((int*)ptr)[i];
                }
        }
        max_num 
 
= max;
        pthread_exit(0);
}
void *min_calc(void * ptr)
{
        int min = 0x7fffffff;
        for(int i=0;i<num_count;i++)
        {
                if(((int*)ptr)[i] < min)
                {
                        min = ((int*)ptr)[i];
                }
        }
        min_num = min;
        pthread_exit(
 
0);
}
int main(int argc,char *argv[])
{

        void *ptr = malloc(100);
        memset(ptr,0,100);

        num_count = argc-1;

        for(int i=0;i<num_count;i++)
        {
                ((int *)ptr)[i] = atoi(argv[i+1]);
        }
        pthread_t tid[3];
        pthread_attr_t attr[3];

        void *(* func[3])(void *ptr) = {avg_calc,max_calc,min_calc};

        for(int i = 0;i<3;i++)
        {
                pthread_attr_init(&attr[i]);
                pthread_create(&tid[i],&attr[i],func[i],ptr);
                pthread_join(tid[i],NULL);
        }

        free(ptr);
        printf("avg_num=%d\nmax_num=%d\nmin_num=%d\n",avg_num,max_num,min_num);

        return 0;
}