括号匹配算法的C语言代码和注释

以下是括号匹配算法的C语言代码和注释：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

// 定义栈结构体
typedef struct {
    char *data;
    int top;
} Stack;

// 初始化栈
Stack *initStack(int size) {
    Stack *s = (Stack *)malloc(sizeof(Stack));
    s->data = (char *)malloc(size * sizeof(char));
    s->top = -1;
    return s;
}

// 判断栈是否为空
int isEmpty(Stack *s) {
    return s->top == -1;
}

// 判断栈是否满了
int isFull(Stack *s, int size) {
    return s->top == size - 1;
}

// 入栈
void push(Stack *s, char c) {
    if (isFull(s, sizeof(s->data))) {
        printf("Error: stack is full\n");
        exit(1);
    }
    s->data[++s->top] = c;
}

// 出栈
char pop(Stack *s) {
    if (isEmpty(s)) {
        printf("Error: stack is empty\n");
        exit(1);
    }
    return s->data[s->top--];
}

// 判断是否匹配
int match(char a, char b) {
    return (a == '(' && b == ')') || (a == '[' && b == ']') || (a == '{' && b == '}');
}

// 判断表达式中的括号是否匹配
int checkExpression(char *expr) {
    Stack *s = initStack(strlen(expr));
    int i;
    for (i = 0; i < strlen(expr); i++) {
        char c = expr[i];
        if (c == '(' || c == '[' || c == '{') {
            push(s, c);
        } else if (c == ')' || c == ']' || c == '}') {
            if (isEmpty(s) || !match(pop(s), c)) {
                return 0;
            }
        }
    }
    return isEmpty(s);
}

// 测试
int main() {
    char expr[] = "int main() { if (i > 0) { printf(\"hello world\\n\"); } }";
    printf("%s\n", checkExpression(expr) ? "matched" : "not matched");
    return 0;
}