set<string> s = { "+", "-", "*", "/", ";", ",", "(", ")", "{", "}" }; bool inSet(const string& c) { return s.find(c) != s.end(); }

这段代码的作用是定义了一个包含特定字符的set集合s，并通过函数inSet判断参数c是否在集合s中。如果在集合s中，函数会返回true，否则返回false。可以这样演示这段代码：[^1]

#include <iostream>
#include <set>
#include <string>

using namespace std;

set<string> s = { "+", "-", "*", "/", ";", ",", "(", ")", "{", "}" };

bool inSet(const string& c) {
    return s.find(c) != s.end();
}

int main() {
    string test1 = "+";
    string test2 = "!";
    if (inSet(test1)) {
        cout << test1 << " is in the set." << endl; // 输出：+ is in the set.
    }
    if (!inSet(test2)) {
        cout << test2 << " is not in the set." << endl; // 输出：! is not in the set.
    }
    return 0;
}