/* Create a C program that receives any number of command line arguments.

 * For each argument, the program will create a thread.

 * Each thread converts any lowercase letters into uppercase letters and prints the initial string and the result.

 */

#include <stdio.h>

#include <stdlib.h>

#include <pthread.h>

#include <string.h>

#include <unistd.h>

typedef struct {

    int id;

    char *s;

} data;



void *upcase(void *arg) {

    data d = *((data*) arg);

    int len = strlen(d.s);

    char *copy = malloc(sizeof(char) * (len + 1));

    strncpy(copy, d.s, len + 1);

    for(int i = 0; i < len; i++) {

        if(copy[i] >= 'a' && copy[i] <= 'z') {

            copy[i] += 'A' - 'a';

        }

    }

    printf("Thread %d - initial argument %s - result %s\n", d.id, d.s, copy);

    return copy;

}



int main(int argc, char *argv[]) {

    int size = argc - 1;

    pthread_t *th = malloc(sizeof(pthread_t) * size);

    data *args = malloc(sizeof(data) * size);

    for(int i = 0; i < size; i++) {

        args[i].id = i;

        args[i].s = argv[i+1];

        if(0 != pthread_create(&th[i], NULL, upcase, &args[i])) {

            perror("Error creating thread");

        }

    }



    for(int i = 0; i < size; i++) {

        char *res = NULL;

        if(0 != pthread_join(th[i], (void **)&res)) {

            perror("Error joining thread");

        } else {

            printf("Thread %d has returned %s\n", i, res);

        }

        if(res != NULL) {

            free(res);

        }

    }

    free(args);

    free(th);

    return 0;

}