Today’s content is a summary of key points for multiple-choice questions in C language for Computer Level 2 (Part 4).
The content is as follows:
61、& Bitwise AND is a binary operator. If both corresponding binary digits are 1, then the result of that bit is 1, otherwise it is 0. 1001&1110 1000
62、User-defined functions can have no return statement, or can have multiple return statements, but regardless of how many return statements are in the function body, the return statement can only execute once. When defined as a void type function, it cannot have a return statement with a return value.
63、In C language, comments are used to help readers better understand the program. They are not converted into binary by the system, so non-executable statements are not converted into binary machine instructions.
64、The sign bit of the two’s complement is inverted to obtain the offset code.
65、The initial state of a linked stack is top=bottom=null, after a series of push and pop operations, if top=bottom=null, then the number of elements in the stack is 0, if top=bottom is not equal to 0, then the number of elements in the stack is 1;
66、Fan-in: the number of direct calls to the upper module of this module;
67、Fan-out: the number of direct calls to the lower module of this module..
68、When executing a called function, if the address of the formal parameter changes, it does not change the address of the actual parameter in the calling function, meaning that the address of the formal parameter is not returned to the corresponding actual parameter.
69、Characteristics of concurrent programs: (1) Loss of program closure (non-reproducibility of program results) (2) Programs and computations are no longer one-to-one corresponding. (3) Mutual constraints of concurrently executing programs.
70、Getchar() cannot be used to read strings, gets( ) can read strings (including spaces) into a character array until a newline character is encountered.
71、An algorithm with no output is meaningless.
72、% can only be used with integer types on both sides, and cannot be used for floating-point calculations.
73、Typedef can declare new type names to replace existing type names, but cannot add new types.
74、The instruction set refers to the complete set of instructions executed by the computer..
75、The three-schema architecture of a database includes: conceptual schema, internal schema, external schema. The conceptual schema describes the logical structure of global data in the database system and is the common data view for all users. The external schema is the user’s data view, which is the data schema seen by the user, derived from the conceptual schema. The internal schema, also known as the physical schema, provides the physical storage and access methods of the database.A conceptual schema can have several external schemas.
76、Register variables cannot be used for address operations.
77、The malloc function allocates int type data of 4 bytes, double is 8 bytes, char is 1 byte.
78、Opening a file with “r” allows only read operations. Opening a file with “w” allows writing. Opening a file with “wb” allows writing to a binary file and can write at a specified file position.
79、Opening an existing file with “a+” does not delete the original file content, allowing for appending and reading operations.
80、
The identifier ptr is a pointer to a one-dimensional array with M integer elements.
All the above content is a personal summary. If there are any errors, please point them out. Thank you for your support, and I wish you success in your exams!
