1 #include <iostream>
2 #include <string>
3 #include <cstdio>
4 #include <stack>
5 using namespace std;
6
7 int main()
8 {
9 int n;
10 string ch;
11 cout << "输入表达式数目: ";
12 cin >> n;
13 while (n--) {
14 stack<char> check;
15 int flag = 0;
16 cout << "输入表达式: ";
17 cin >> ch;
18 int len = ch.size();
19 int i = 0;
20 for (i = 0; i < len; i++) {
21 //"("、")"、"["、"]"、"{"、"}"、"<"、">"
22 if (ch[i] == '(' || ch[i] == '[' || ch[i] == '{' || ch[i] == '<') {
23 check.push(ch[i]); flag = 0; //左括号直接进栈
24 }
25 else if (ch[i] == ')' || ch[i] == ']' || ch[i] == '}' || ch[i] == '>') {
26 if (check.empty()) { //遇到右括号时,栈顶为空则为不匹配
27 flag = 1; break;
28 }
29 else {
30 if ((check.top() == '(' && ch[i] == ')') || (check.top() == '[' && ch[i] == ']') ||
31 (check.top() == '{' && ch[i] == '}') || (check.top() == '<' && ch[i] == '>')) {
32 flag = 0; check.pop(); //出栈左括号,继续判断
33 }
34 else { //如果左右不匹配,则退出判断
35 flag = 1; break;
36 }
37 }
38 }
39 }
40 if (check.empty() && !flag) { //如果栈为空,且没有右括号出现--匹配
41 printf("匹配\n");
42 }
43 else if (!check.empty() && !flag){
44 cout << "不匹配: 多左括号" << check.top() << endl;
45 }
46 else if (flag && check.empty()) {
47 cout << "不匹配: 多右括号" << ch[i] << endl;
48 }
49 else if (flag && !check.empty()) {
50 switch(ch[i]) {
51 case ')' : cout << "不匹配: " << check.top()
52 << "与" << ch[i] << "匹配错\n"; break;
53 case ']' : cout << "不匹配: " << check.top()
54 << "与" << ch[i] << "匹配错\n"; break;
55 case '}' : cout << "不匹配: " << check.top()
56 << "与" << ch[i] << "匹配错\n"; break;
57 case '>' : cout << "不匹配: " << check.top()
58 << "与" << ch[i] << "匹配错\n"; break;
59 default : cout << "不匹配\n"; break;
60 }
61 }
62 cout << endl;
63 }
64 return 0;
65 }
