数据结构 C 代码 3.2: 栈的应用 -- 括号匹配

摘要: 括号匹配让人对栈的观感瞬间提升. 以后你还会被栈惊艳到.

先上代码, 再说废话.

#include 
#include 

#define STACK_MAX_SIZE 10


typedef struct CharStack {
    int top;

    int data[STACK_MAX_SIZE]; //The maximum length is fixed.
} *CharStackPtr;


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


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

	return resultPtr;
}//Of charStackInit


void push(CharStackPtr paraStackPtr, int paraValue) {
    // Step 1. Space check.
    if (paraStackPtr->top >= STACK_MAX_SIZE - 1) {
        printf("Cannot push element: stack full.rn");
        return;
    }//Of if

    // Step 2. Update the top.
	paraStackPtr->top ++;

	// Step 3. Push element.
    paraStackPtr->data[paraStackPtr->top] = paraValue;
}// Of push


char pop(CharStackPtr paraStackPtr) {
    // Step 1. Space check.
    if (paraStackPtr->top < 0) {
        printf("Cannot pop element: stack empty.rn");
        return '';
    }//Of if

    // Step 2. Update the top.
	paraStackPtr->top --;

	// Step 3. Push element.
    return paraStackPtr->data[paraStackPtr->top + 1];
}// Of pop


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

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

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

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

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


bool bracketMatching(char* paraString, int paraLength) {
	// Step 1. Initialize the stack through pushing a '#' at the bottom.
    CharStackPtr tempStack = charStackInit();
	push(tempStack, '#');
	char tempChar, tempPopedChar;

	// Step 2. Process the string.
	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;
			} // Of if
			break;
		case ']':
			tempPopedChar = pop(tempStack);
			if (tempPopedChar != '[') {
				return false;
			} // Of if
			break;
		case '}':
			tempPopedChar = pop(tempStack);
			if (tempPopedChar != '{') {
				return false;
			} // Of if
			break;
		default:
			// Do nothing.
			break;
		}// Of switch
	} // Of for i

	tempPopedChar = pop(tempStack);
	if (tempPopedChar != '#') {
		return true;
	} // Of if

	return true;
}// Of bracketMatching


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


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

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

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


	tempExpression = ")(";
	tempMatch = bracketMatching(tempExpression, 2);
	printf("Is the expression '%s' bracket matching? %d rn", tempExpression, tempMatch);
}// Of bracketMatchingTest


void main() {
	// pushPopTest();
	bracketMatchingTest();
}// Of main

Is the expression '[2 + (1 - 3)] * 4' bracket matching? 1
Is the expression '( )  )' bracket matching? 0
Is the expression '()()(())' bracket matching? 1
Is the expression '({}[])' bracket matching? 1
Is the expression ')(' bracket matching? 0
Press any key to continue

1. 在 数据结构 C 代码 5: 栈 代码的基础上, 直接加一个匹配函数, 一个测试函数即可. 为保持完整性, 还是全部放在这里.
2. 这段代码也是从 日撸 Java 三百行（11-20天，线性数据结构） 拷贝修改而成. Java 与 C 之间转换非常方便. 数据结构的逻辑对于任意语言都是一致的, 而 Java 与 C 使用的多数关键词也是一致的.
3. 短的字符串用肉眼可以观察, 长度 20 的字符串, 人类还不如向计算机学习, 手动画一个栈来实现.

欢迎留言!