C++检测字符串中有效的括号个数

 匹配一个字符串buf中，连续包换运算符reg的次数：

#include <iostream>

//return 返回匹配的字符个数
//buf, 要检测的字符串
//reg, 包含的连续运算符
int GetMatchCount(std::string& buf, std::string& reg)
{
    int nMatchCount = 0;

	if (reg.empty())
		return nMatchCount;

    std::string matchReg = reg;
    for (int i = 0; i < buf.length(); i++)
    {
        if (buf[i] == matchReg.front())
        {
            matchReg.erase(matchReg.begin());
        }

        if (matchReg.empty())
        {
            nMatchCount ++;

            matchReg = reg;
        }
    }

    return nMatchCount;
}

使用示例：

int main()
{

    std::string text = "[][][[(Hello World!)]";
    std::string reg = "[]";

    std::cout << "match string:\"" << text << "\" | reg(\"" << reg << "\")" << std::endl;
    int count = GetMatchCount(text, reg);
    std::cout << "match count: " << count << std::endl;

    return 0;
}

运行结果：