added constructor function

qscr/c/gai/fixedynarr.c

@@ -10,29 +10,39 @@ struct IntArray{
 
 void readintarray(struct IntArray *input) {
   printf("inputlength:%zu\n", input->length);
-  for (int i = 0; i < input->length; i++) {
+  for (size_t i = 0; i < input->length; i++) {
 	printf("digit:%d = %d\n", i, input->data[i]);
   }
 }
 
+struct IntArray *create_int_array(size_t length) {
+  struct IntArray *myintarray = malloc(sizeof(struct IntArray)); /* allocate memory for struct */
+
+  myintarray->data = malloc(sizeof(int) * length); 	/* make sure the pointer in the struct points to the array */
+  myintarray->length = length;  //forgot to actually assign a value to the struct
+
+  if (myintarray->data == NULL) {
+	exit(0);
+  }
+  
+  return myintarray;
+}
+
 int main() {
   srand(time(NULL));
   printf("how many numbers?\n");
   int length;
   scanf("%d", &length);
 
-  struct IntArray *myintarray = malloc(sizeof(struct IntArray)); /* allocate memory for struct */
-  int *myarray = malloc(sizeof(int) * length); /* allocate memory for array that the struct points to */
+  struct IntArray *myintarray = create_int_array(length);
 
-  myintarray->data = myarray; 	/* make sure the pointer in the struct points to the array */
-  myintarray->length = length;  //forgot to actually assign a value to the struct
   for (int i = 0; i < length; i++) {
     myintarray->data[i] = rand() % 10;
     printf("number:%d = %d\n",i,myintarray->data[i]);
-  }
+  }  
 
   readintarray(myintarray);
-  
+
   free(myintarray->data);
   free(myintarray);