Part B

HW9a.c

@@ -26,8 +26,9 @@ void printStructure() {
     // Start iterating after the the latest entry (total_size-current_size) and continue until end (total_size)
     for(int i=total_size-current_size;i < total_size;i++) {
            // Add comma if not last (or only) slot, else add newline
-           if (i + 1 != total_size) {printf("%d, ",*(ptr + i));}
-           else {printf("%d\n",*(ptr + i));}
+           printf((i + 1 != total_size)?"%d, ":"%d\n",*(ptr + i));
+           //if (i + 1 != total_size) {printf("%d, ",*(ptr + i));}
+           //else {printf("%d\n",*(ptr + i));}
     }
     
 }

HW9b.c

@@ -0,0 +1,71 @@
+/*
+
+    COS135 HW9b
+    Nicholas Pease
+    Dynamic LIFO Stack
+
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+
+int ptr_size = 0;
+char* ptr;
+
+void push(char addition) {
+    // Deal with allocation every time push is called and pop. If not initialized, the source is NULL
+    ptr = realloc((ptr_size == 0)? NULL: ptr, (ptr_size+1)*sizeof(char));
+    *(ptr+ptr_size) = addition;
+    ptr_size++;
+}
+
+char pop() {
+    char removal = *(ptr+ptr_size-1);
+    ptr_size--;
+    ptr = realloc((ptr_size == 0)? NULL: ptr, (ptr_size)*sizeof(char));
+    return removal;
+}
+
+void print() {
+    for (int i = ptr_size - 1; i >= 0; i--)
+        printf("%c\n",*(ptr+i));
+        /*
+    for (int i = 0; i < ptr_size; i++)
+        printf((i + 1 != ptr_size)?"%c, ":"%c\n",*(ptr+i));
+        */
+}
+
+int main() {
+    char input[20] = "";
+    while(strncmp("quit",input,4)!= 0) {
+        printf("Enter command (push, print, or quit): ");
+        fgets(input,20,stdin);
+        // Strip newline character from input (fgets)
+        for (int i=0;i<strlen(input);i++) if (input[i] == '\n') input[i] = '\0';
+
+
+        // Check if the first 4 letter of string are push, then process string for remaining integer
+        if (strncmp("push",input,4) == 0) {
+            if (ptr_size != 10) {
+                // Extract char from push. Should be slot 5
+                char temp = input[5];
+                push(temp);
+            } else {
+                printf("Error: Maximum elements in the stack\n");
+            }
+        }
+
+        if (strncmp("pop",input,3) == 0)
+            printf("Popped: %c \n",pop());
+
+        // If the first 5 letters of the input are "print", simply call printStructure() which requires no data input
+        if (strncmp("print",input,5) == 0 && ptr_size > 0)
+            print();
+    }
+    // Freeup memory and leave
+    printf("Bye\n");
+    free(ptr);
+    return 0;
+}