1、 易安信 2022 技術(shù)類面試題第1題： 在C+中，變量用時聲明是為什么 第2題： 命名空間的作用 第3題： protected成員函數(shù)能被怎么調(diào)用 第4題： int, char, short, long的字節(jié)數(shù) 第5題： int a1010; int *b10; 以下哪個正確 a34 = 91; b34 = 91; a1 =NULL; b1 = a2; 第6題： 1210, 12|10, 1210, 31, 31的結(jié)果 第7題： x86_64系統(tǒng)下 struct int i; char c; double d; ; union int i; char c; double d; ; char

2、s100; long c; sizeof的值 第8題： An employee has one or two managers, and one manager manages one or more employees. In database conceptual design, the relationship between entity sets employee and manager is A one to one B one to many C many to one D many to many E none of the above 第9題： There are two r

3、elations R1(A, B, C) and R2(B, D, E). Which of following techniques CANNOT be used to improve the performance of the natural join of the two relations? A make use of multiple parallel processes on a multi-core machine to implement the join algorithm B increase the CPU L2 cache hit ratio of the join

4、algorithm implementation C partition the relations to different machines by using join attributes and execute the join on many machines in parallel D when the number of tuples in R2 is large and the number of tuples in R1 is small, build and index on R1 and use index join method E none of the above

5、第10題： Which of the following statements about checkpoints(with log-based recovery schemes) in databases are/is NOT correct? A checkpoints are used to decrease the time used for failure recovery B checkpoints are done periodically in database to assure ACID properties of transactions C periodic check

6、points decreased the number of log entries that need to be redone during recovery D during checkpointing, updated disk blocks are written to disk E none of the above 第11題： There is a huge relation R(A,B,C) of size M and A is the primary key. The tuples in R are sorted by using A and no index is buil

7、t for R. Each disk block size of b, and each block read takes N seconds. To find a tuple in R with A =17954 the estimated optimized cost is A M*N/b B N*log(M/b) C M*N/(2b) D (M+N)/b E log(M*N)/b 第12題： Which of the following descriptions of reader/writer locks are/is wrong? A caller cannot upgrade it

8、s read lock(already obtained) to write lock B caller can downgrade its write lock(already obtained) to read lock C caller can get read lock if there is no write lock held by others D multiple callers can hold a read lock at the same time E only one caller can hold a write lock at a time 第13題： 兩頁的內(nèi)存，四頁的文件，讀取挨次為1 2 1 3 1 2 4 2 1 3 1 2 4 2 1 2 3 4 3 1，F(xiàn)IFO，問cache hit ratio為多少 第14題： which one is not above IP DNS, SNMP, HTTP, ARP, NTP 第15題： #include iostream using namespace void main() cout “hello world” endl; 修改程序，不能修改主程序，使其輸出為 initiate hello world destroy 第16題： spinlock與mutex