数据结构-7（栈的应用--括号匹配）

在一个表达式中含有圆括号或方括号等来表示运算的优先级，将这些括号提取出来就构成了括号序列

（1）建立空栈

typedef struct CharStack {
    int top;

    int data[STACK_MAX_SIZE];
} 

（2）初始化

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

	return resultPtr;
}

（3）打印

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

（4）进栈（功能表达）

void push(CharStackPtr paraStackPtr, int paraValue) {

    if (paraStackPtr->top >= STACK_MAX_SIZE - 1) {
        printf("Cannot push element: stack full.rn");
        return;
    }

	paraStackPtr->top ++;

    paraStackPtr->data[paraStackPtr->top] = paraValue;
}

（5）出栈（功能表达）

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

	paraStackPtr->top --;

    return paraStackPtr->data[paraStackPtr->top + 1];
}

（6）进出栈（功能实现）

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

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

	for (char 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");
}

（7）检验括号是否匹配（功能实现）

bool bracketMatching(char* paraString, int paraLength) {

    CharStackPtr tempStack = charStackInit();
	push(tempStack, '#');
	char tempChar, tempPopedChar;

	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;
		}
	}

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

	return true;
}

（8）检验括号是否匹配（功能表达）

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);
}