C语言数据结构 3：栈和括号匹配

栈是一种操作受限的线性表只允许从一端插入和删除数据。栈有两种存储方式，即线性存储和链接存储（链表）。栈的一个最重要的特征就是栈的插入和删除只能在栈顶进行，所以每次删除的元素都是最后进栈的元素，故栈也被称为后进先出（LIFO）表。每个栈都有一个栈顶指针，它初始值为-1，且总是指向最后一个入栈的元素，栈有两种处理方式，即进栈（push）和出栈（pop）。

代码实现：

#include 
#include 

#define STACK_MAX_SIZE 10


typedef struct CharStack{
	int top;
	int data[STACK_MAX_SIZE];
}*CharStackPtr;


void outputStack(CharStackPtr paraStack) {
	for(int i=0;i<=paraStack->top;i++) {
		printf("%c ",paraStack->data[i]);
	}
	printf("rn");
}


CharStackPtr charStackInit() {
	CharStackPtr resultPtr = (CharStackPtr)malloc(sizeof(CharStack));
	resultPtr->top = -1;

	return resultPtr;
}


void push(CharStackPtr paraStackPtr, int paraValue) {
	//检查是否还有剩余空间
	if (paraStackPtr->top >= STACK_MAX_SIZE - 1) {
		printf("Cannot push element: stack full.rn");
		return;
	}

	//更新top的值
	paraStackPtr->top++;

	//放入元素
	paraStackPtr->data[paraStackPtr->top]=paraValue;
}


char pop(CharStackPtr paraStackPtr) {
	// 检查栈是否为空
	if (paraStackPtr->top < 0) {
		printf("Cannot pop element: stack empty.rn");
		return '';
	}

	// 更新top
	paraStackPtr->top --;

	// 返回出栈的数据
	return paraStackPtr->data[paraStackPtr->top + 1];
}


void pushPopTest() {
	char ch;
	printf("---- pushPopTest begins. ----rn");

	CharStackPtr tempStack = charStackInit();
	printf("After initialization, the stack is: ");
	outputStack(tempStack);

	for (ch = 'a'; ch < 'm'; ch ++) {
		printf("Pushing %c.rn", ch);
		push(tempStack, ch);
		outputStack(tempStack);
	}

	for (int i = 0; i < 3; i ++) {
		ch = pop(tempStack);
		printf("Pop %c.rn", ch);
		outputStack(tempStack);
	}

	printf("---- pushPopTest ends. ----rn");
}

int main() {
	pushPopTest();
}

括号匹配是栈的最基本应用，即给定一个字符串确定其中的各个括号是否匹配，例如“（）{}”为匹配的，而“（ [ ) ] ” 不匹配。

代码：

#include 
#include 

#define STACK_MAX_SIZE 10


typedef struct CharStack{
	int top;
	int data[STACK_MAX_SIZE];
}*CharStackPtr;


void outputStack(CharStackPtr paraStack) {
	for(int i=0;i<=paraStack->top;i++) {
		printf("%c ",paraStack->data[i]);
	}
	printf("rn");
}


CharStackPtr charStackInit() {
	CharStackPtr resultPtr = (CharStackPtr)malloc(sizeof(CharStack));
	resultPtr->top = -1;

	return resultPtr;
}


void push(CharStackPtr paraStackPtr, int paraValue) {
	//检查是否还有剩余空间
	if (paraStackPtr->top >= STACK_MAX_SIZE - 1) {
		printf("Cannot push element: stack full.rn");
		return;
	}

	//更新top的值
	paraStackPtr->top++;

	//放入元素
	paraStackPtr->data[paraStackPtr->top]=paraValue;
}



char pop(CharStackPtr paraStackPtr) {
	// 检查栈是否为空
	if (paraStackPtr->top < 0) {
		printf("Cannot pop element: stack empty.rn");
		return '';
	}

	// 更新top
	paraStackPtr->top --;

	// 返回出栈的数据
	return paraStackPtr->data[paraStackPtr->top + 1];
}


bool bracketMatching(char* paraString, int paraLength) {
	// 创建一个栈，同时压入'#'用于最终判断
	CharStackPtr tempStack = charStackInit();
	push(tempStack, '#');

	char tempChar, tempPopedChar;

	// 循环判断
	for (int i = 0; i < paraLength; i++) {
		tempChar = paraString[i];

		switch (tempChar) {
		case '(':
		case '[':
		case '{':
			push(tempStack, tempChar);
			break;
		case ')':
			tempPopedChar = pop(tempStack);
			if (tempPopedChar != '(') {
				return false;
			}
			break;
		case ']':
			tempPopedChar = pop(tempStack);
			if (tempPopedChar != '[') {
				return false;
			}
			break;
		case '}':
			tempPopedChar = pop(tempStack);
			if (tempPopedChar != '{') {
				return false;
			}
			break;
			default:
				break;
		}
	}

	// 判断现在位于栈顶的元素是否为'#'
	tempPopedChar = pop(tempStack);
	if (tempPopedChar != '#') {
		return false;
	}

	return true;
}


void bracketMatchingTest() {
	char tempExpression0[] = "[2 + (1 - 3)] * 4";
	bool tempMatch = bracketMatching(tempExpression0, 17);
	printf("Is the expression '%s' bracket matching? %d rn", tempExpression0, tempMatch);


	char tempExpression1[] = "( )  )";
	tempMatch = bracketMatching(tempExpression1, 6);
	printf("Is the expression '%s' bracket matching? %d rn", tempExpression1, tempMatch);

	char tempExpression2[] = "()()(())";
	tempMatch = bracketMatching(tempExpression2, 8);
	printf("Is the expression '%s' bracket matching? %d rn", tempExpression2, tempMatch);

	char tempExpression3[] = "({}[])";
	tempMatch = bracketMatching(tempExpression3, 6);
	printf("Is the expression '%s' bracket matching? %d rn", tempExpression3, tempMatch);


	char tempExpression4[] = ")(";
	tempMatch = bracketMatching(tempExpression4, 2);
	printf("Is the expression '%s' bracket matching? %d rn", tempExpression4, tempMatch);
}

int main() {
	bracketMatchingTest();
}