Update fact.c

fact.c

 //
-// Modified on 24/04/2020.
+// Modified on 26/04/2020.
 //
 #include <errno.h>
 #include <sys/types.h>
@@ -141,7 +141,7 @@ void *read_write() {
             fprintf(f.out, "\n");
             free(dividers);
         } else {
-            fprintf(f.out, "The number %lu is not > 2, discarded \n", number);
+            fprintf(f.out, "The number %lu is not > 2, discarded\n", number);
 	    }
     }
     pthread_exit((void *) 0); // thread exit: normal termination => 0
@@ -166,4 +166,70 @@ int main (int argc, char *argv[]) {
         inputfile = argv[1];
         outputfile = argv[2];
         printf("Thread number not mentioned\n");
-        printf("The default threads number is %d\n", DEFAULT_NO_THREADS);
+        printf("The default threads number is %d\n", DEFAULT_NO_THREADS);
\ No newline at end of file
+    } else if(argc == 5) {
+        thread_arg = argv[1];
+        if(strcmp(thread_arg, "-N") != 0) {
+            printf("%s\n", "Wrong input of the option\n Use option  \"-N\"\n");
+            exit(EXIT_FAILURE);
+        }
+        NO_THREADS = atoi(argv[2]);
+        if(NO_THREADS > MAX_NO_THREADS) {
+            printf("Threads requested > %d\n", MAX_NO_THREADS);
+            exit(EXIT_FAILURE);
+        }
+        inputfile = argv[3];
+        outputfile = argv[4];
+    } else {
+        printf("%s\n", "Many or few arguments\n");
+        printf("Correct command syntax:\n");
+        printf("./fact [-N number_of_threads] input_file.txt output_file.txt\n\n");
+        exit(EXIT_FAILURE);
+    }
+ /*
+  * START CLOCK to measure CPU time
+  * calculate programme performance
+  */
+  /*
+    clock_t start, end;
+    double cpu_time_used;
+    start = clock();
+  */
+    // Open input and output files
+    f.in = fopen(inputfile, "r");
+    f.out = fopen(outputfile, "a+");
+    if ((f.in == NULL) || (f.out == NULL)) {
+        printf("Incorrect input_file or output_file name\n");
+        exit(EXIT_FAILURE);
+    }
+
+    pthread_t thread[NO_THREADS]; // thread IDs
+    // INITIALIZE MUTEX "mutex_readwrite"
+    if (pthread_mutex_init(&mutex_readwrite , NULL) != 0){
+        printf("\n mutex init failed-mutex_readwrite\n");
+        exit(EXIT_FAILURE);
+    }
+    int i;
+    for (i = 0; i < NO_THREADS; i++) {
+        pthread_create(&thread[i], NULL, (void*)read_write, NULL);
+    }
+    for (i = 0; i < NO_THREADS; i++) {
+        pthread_join(thread[i], NULL);
+    }
+ /* END CLOCK to measure CPU time */
+ /*
+    end = clock();
+    cpu_time_used = ((double) (end - start)) / CLOCKS_PER_SEC;
+    fprintf(f.out, "\nThe programme execution needed %.3f seconds\n\n", cpu_time_used);
+    printf("\nThe programme execution needed %.3f seconds", cpu_time_used);
+    printf("\n -- Programme end --\n");
+ */
+    // Eliminate mutex "mutex_readwrite"
+    if (pthread_mutex_destroy(&mutex_readwrite) != 0){
+        printf("\nmutex_destroy-mutex_readwrite %s\n", strerror(errno));
+        exit(EXIT_FAILURE);
+    }
+    fclose(f.in);
+    fclose(f.out);
+    return (EXIT_SUCCESS);
+}
\ No newline at end of file