使用带有struct key的map会导致崩溃

Question

我创建了一个简单的地图使用struct作为键但在运行时崩溃。 你能指出这个问题吗？非常感谢。

放置第3项时代码崩溃。

...
typedef struct pmjob
{
    std::string jobId;
    std::string jobGroup;
    int reportingPeriod;
    int compressionType;
    bool operator == (const struct pmjob &other) const
    {
        return ((jobGroup.compare(other.jobGroup) == 0) && (reportingPeriod == other.reportingPeriod));
    }

    bool operator < (const struct pmjob &other) const
    {
        if (reportingPeriod < other.reportingPeriod)
        {
            if(jobGroup.compare(other.jobGroup) == 0)
                return false;
        }
        return true;
        //return ((reportingPeriod < other.reportingPeriod) || (jobGroup.compare(other.jobGroup)));
    }
}PMJob;

typedef std::map<PMJob, int> PMJobMap;
PMJobMap List;
typedef std::pair<PMJob, int> PMJobPair;

Answer 1

您的比较器无效。

bool operator < (const struct pmjob &other) const

它没有提供严格的弱排序。

有效比较器的示例：

bool operator < (const struct pmjob &other) const
{
    // first compare most important member
    if (reportingPeriod < other.reportingPeriod) {
        return false;
    }
    if (other.reportingPeriod < reportingPeriod) {
        return true;
    }

    // less important member
    if (compressionType < other.compressionType) {
        return false;
    }
    if (other.compressionType < compressionType) {
        return true;
    }

    if (jobId < other.jobId) {
        return false;
    }
    if (other.jobId < jobId) {
        return true;
    }

    if (jobGroup < other.jobGroup) {
        return false;
    }
    if (other.jobGroup < jobGroup) {
        return true;
    }

    return false;
}

或使用std::tie：

bool operator < (const struct pmjob &other) const
{
    return std::tie(jobId, jobGroup, reportingPeriod, compressionType) < 
        std::tie(other.jobId, other.jobGroup, other.reportingPeriod, other.compressionType);
}