2.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <pthread.h>

typedef struct _sync_int{
    int v;
    pthread_mutex_t lock;
}sync_int;

sync_int n;
char fname[32];

void* fun(void* arg){
    int br=*(int*) arg;
    int curr;
    FILE* f;
    f=fopen(fname, "r+");

    while(fscanf(f, "%d", &curr)==1){
        if(curr==br){
            pthread_mutex_lock(&n.lock);
            n.v++;
            pthread_mutex_unlock(&n.lock);
        }
    }

    return (void*)0;
}

int main(int argc, char** argv){
    int i;
    int args[10];
    pthread_t pid_a[10];
    n.v=0;
    strcpy(fname, argv[1]);

    pthread_mutex_init(&n.lock, NULL);

    for(i=0;i<10;i++){
        args[i]=i;
        pthread_create(&pid_a[i], NULL, fun, &args[i]);
    }

    for(i=0;i<10;i++)
        pthread_join(pid_a[i], NULL);

    pthread_mutex_destroy(&n.lock);

    printf("%d\n", n.v);

    return 0;
}