feat(codes/c): Update array_stack.c codes (krahets#289)

codes/c/chapter_stack_and_queue/array_stack.c

@@ -6,38 +6,118 @@
 
 #include "../include/include.h"
 
-
+/* 基于数组实现的栈 */
 struct ArrayStack {
-    int *array;
-    size_t stkSize;
+    int *stackTop;
+    int size;
+    int capacity;
 };
 
 typedef struct ArrayStack ArrayStack;
 
-void new(ArrayStack* stk) {
-
+/* 内部调用 */
+/* 获取栈容量 */
+static int capacity(ArrayStack *stk) {
+    return stk->capacity;
 }
 
-size_t size(ArrayStack* stk) {
+/* 栈自动扩容 */
+static void extendCapacity(ArrayStack *stk) {
+    // 先分配空间
+    int newCapacity = capacity(stk) * 2;
+    int *extend = (int *)malloc(sizeof(int) * newCapacity);
+    int *temp = stk->stackTop;
 
-}
+    // 拷贝旧数据到新数据
+    for(int i=0; i<stk->size; i++)
+        extend[i] = temp[i];
 
-bool empty(ArrayStack* stk) {
+    // 释放旧数据
+    free(temp);
 
+    // 更新新数据
+    stk->stackTop = extend;
+    stk->capacity = newCapacity;
 }
 
-void push(ArrayStack* stk, int num) {
+/* 构造函数 */
+void newArrayStack(ArrayStack *stk) {
+    stk->capacity = 10;
+    stk->size = 0;
+    stk->stackTop = (int *)malloc(sizeof(int) * stk->capacity);
+}
 
+/* 析构函数 */
+void delArrayStack(ArrayStack *stk) {
+    stk->capacity = 0;
+    stk->size = 0;
+    free(stk->stackTop);
 }
 
-void pop(ArrayStack* stk) {
+/* 获取栈的长度 */
+int size(ArrayStack *stk) {
+    return stk->size;
+}
 
+/* 判断栈是否为空 */
+bool empty(ArrayStack *stk) {
+    return size(stk) == 0;
 }
 
-int top(ArrayStack* stk) {
+/* 访问栈顶元素 */
+int top(ArrayStack *stk) {
+    return stk->stackTop[size(stk) - 1];
+}
+
+/* 入栈 */
+void push(ArrayStack *stk, int num) {
+    if (size(stk) == capacity(stk)) 
+        extendCapacity(stk);        // 需要扩容
+
+    stk->stackTop[size(stk)] = num;
+    stk->size++;
+}
 
+/* 出栈 */
+void pop(ArrayStack *stk) {
+    int num = stk->stackTop[size(stk) - 1];
+    stk->size--;
 }
 
+/* Driver Code */
 int main() {
+    /* 初始化栈 */
+    ArrayStack stack;
+    newArrayStack(&stack);
+
+    /* 元素入栈 */
+    push(&stack, 1);
+    push(&stack, 3);
+    push(&stack, 2);
+    push(&stack, 5);
+    push(&stack, 4);
+
+    printf("栈 stack = ");
+    printArray(stack.stackTop, size(&stack));
+
+    /* 访问栈顶元素 */
+    int stackTop = top(&stack);
+    printf("栈顶元素 top = %d\r\n", stackTop);
+
+    /* 元素出栈 */
+    pop(&stack);
+    printf("出栈元素 pop = %d, 出栈后 stack =  ", stackTop);
+    printArray(stack.stackTop, size(&stack));
+
+    /* 获取栈的长度 */
+    int stackSize = size(&stack);
+    printf("栈的长度 size = %d\r\n", stackSize);
+
+    /* 判断是否为空 */
+    bool isEmpty = empty(&stack);
+    printf("栈是否为空 = %s\r\n", isEmpty ? "yes" : "no");
+
+    /* 析构函数 */
+    delArrayStack(&stack);
     return 0;
 }