Your question is Legacy Design Review for Bugs. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
A Software Engineer candidate at Veeam, which builds backup and data-protection software, was shown the following C++ class from a legacy job-scheduling module and asked whether the constructor is correct.
class BackupJob {
public:
BackupJob(const std::string& jobName, int retentionDays) {
memset(this, 0, sizeof(BackupJob));
name = jobName;
retention = retentionDays;
logStartupEvent();
}
virtual ~BackupJob() {}
virtual void logStartupEvent() {
std::cout << "Starting backup job: " << name << std::endl;
}
virtual bool run() {
return retention > 0;
}
void schedule(int delaySeconds) {
nextRunTime = time(nullptr) + delaySeconds;
}
private:
std::string name;
int retention;
time_t nextRunTime;
};
Say clearly whether this constructor is correct, and explain in detail what goes wrong at runtime and why, thinking about what the compiler has already done to this object before the constructor body even starts running.