X-Git-Url: https://git.danieliu.xyz/?a=blobdiff_plain;f=include%2Fcstack.h;h=d6ca4079720637a3d3e9b014bc6e66cf08499e19;hb=b416f18295f7edcb5474396a6b26a59fd5ddb1f5;hp=315dacbc840236d610e2ba6bc4c3e9ce25f31e75;hpb=0f870f29388a36d32ec9ffaabe9ffe03edc038c0;p=smdp.git

diff --git a/include/cstack.h b/include/cstack.h
index 315dacb..d6ca407 100644
--- a/include/cstack.h
+++ b/include/cstack.h
@@ -1,6 +1,26 @@
 #if !defined( CSTACK_H )
 #define CSTACK_H
 
+/*
+ * A implementation of a char stack in heap memory.
+ *
+ * struct: cstack_t which defines char stack type in heap memory
+ *
+ * function: cstack_init to intialize struct of type cstack_t
+ * function: cstack_t->push to add one char on top if the stack
+ * function: cstack_t->pop to remove the top char from the stack
+ * function: cstack_t->top to test if the top char is a given char
+ * function: cstack_t->empty to test if the stack is empty
+ * function: cstack_t->delete to free the allocated memory
+ *
+ * Example:
+ *      cstack_t *p = cstack_init();
+ *      (p->push)(p, 'X');
+ *      printf("%c\n", (p->pop)(p));
+ *      (p->delete)(p);
+ *
+ */
+
 typedef struct _cstack_t {
     char *content;
     size_t alloc;
@@ -8,7 +28,7 @@ typedef struct _cstack_t {
     int head;
     void (*push)(struct _cstack_t *self, char c);
     char (*pop)(struct _cstack_t *self);
-    char (*top)(struct _cstack_t *self);
+    int (*top)(struct _cstack_t *self, char c);
     int (*empty)(struct _cstack_t *self);
     void (*delete)(struct _cstack_t *self);
 } cstack_t;
@@ -16,7 +36,7 @@ typedef struct _cstack_t {
 cstack_t *cstack_init();
 void cstack_push(cstack_t *self, char c);
 char cstack_pop(cstack_t *self);
-char cstack_top(cstack_t *self);
+int cstack_top(cstack_t *self, char c);
 int cstack_empty(cstack_t *self);
 void cstack_delete(cstack_t *self);