Merge branch '2-add-stack-data-stucture' into 'main'

Resolve "Add stack data stucture"

Closes #2

See merge request !2

stack.h

+#ifndef _STACK_H_
+#define _STACK_H_
+
+typedef struct _stack {
+    int *data;
+    int capacity;
+    int top;
+} stack;
+
+#endif