Solution Exercise 1.1

Transcription

1 Solution Exercise 1.1 Part I Fill in the blanks with the most appropriate answers. 1. A Program is a sequence of step-by-step instructions that a computer executes in order to solve a problem or to perform a task. 2. A digital computer system consists of hardware and software. 3. The hardware consists of the physical components of a digital computer system. 4. The software is the collection of programs that a computer can execute. 5. A byte is a group of 8 consecutive bits. 6. The address of a byte corresponds to its relative position in the main memory. 7. The contents of a byte is the bit pattern that it represents. 8. The main memory holds the data to be processed by the computer, and the program that it must execute in order to process it. 9. The _central processing unit_(cpu) controls the operations of the different components of a computer, and executes the instructions of a program. 10. The control unit (CU) controls the operations of the different components of a computer, and also interprets (or decodes) each instruction of a program. 11. The arithmetic and logic unit (ALU) executes the instructions of a program. 12. registers are special high-speed memory locations within the CPU that are used by programmers or the CPU to hold certain data. 13. The input system consists of the input devices and their controllers. 14. The output system consists of the _output devices and their controllers. 15. For an output device, the controller accepts incoming data (as a sequence of bits) from the computer and converts it into the signals used by that device. 16. For an input device, the controller accepts signals from the device that it converts into sequences of bits to be used inside the computer. 17. A secondary storage is used to permanently save data and programs for future use inside the computer. 18. In order to use a particular secondary storage on a computer, that computer must be equipped with a drive for that type of secondary storage and a controller for the communication between the computer and the drive. 19. A computer system peripheral is the collection of input devices, output devices, and the drives on that computer system. 20. The system interconnection consists of the wiring and the devices that allow data and control codes to move from one part of the computer system to another.

2 Part II 1. Main memory, the central processing unit (CPU), the input system, and the output system. 2. The control unit (CU), the arithmetic and logic unit (ALU), and the registers. 3. a. keyboards, mice, microphones; b. monitors, printers, speakers c. floppy disks, hard disks, tapes. 4. a. the main memory holds the programs to be executed by the CPU, and their data. b. An input device transmits information from the outside world to the computer. c. An output device transmits information from the computer to the outside world. d. The CPU controls the operations of the different components of a computer, and executes the instructions of a program. e. A secondary storage is used to hold programs and data for future use inside the computer. Solution Exercise 1.2 Fill in the blanks with the most appropriate answers. 1. An application program is a program that is used to perform a specific task or to solve a particular problem for its user. 2. A system program is a program that is used for the operation of the computer. 3. A wordprocessor is a program that lets its users create documents with formatting features. It also inserts hidden codes in a document in order to obtain certain features such as boldfacing, underlining, italic,... etc. 4. A data base management system is a program that lets its users create tables of information, and also provides for easy access and update of information in those tables. 5. A spreadsheet program is a program that lets its users create electronic spreadsheets. 6. An editor is a program that reads characters from the keyboard and places them into a file. 7. An operating system is a program that manages all the computer resources, making sure that resources such as the main memory, the printer, the hard disk,..., etc are used properly. 8. An operating system is a program that provides an interface to the hardware that is easy to understand and use in other programs. 9. A shell or command processor is a program that provides the access of the computer system to users. Solution Exercise Input of information; processing of information; and output of the result(s). 2. In a memory location 3. As a sequence of bits 4. a. one byte. b four bytes. 5. It is the address of the first byte of that memory location. 6. In machine language. 7. As sequences of bits. 8. No. Because both computers have different machine languages

3 9. COBOL, Fortran, Pascal, C/C++, Java, Basic 10. Translate it into the machine language of the IBM PC. 11. No. Because both computers have different machine languages 12. A compiler takes a program in a high level language and produces another program in machine language. An interpreter on the other hand takes a program in a high level language with its input data, and executes that program on the machine and produces the output of that program. It does not produce a program in machine language and a compiler does not execute a program. 13. Java, Basic. Solution Exercise 1.4 Line # Statements /Comments /* Program to read two integer values, to compute their sum, and to print the result */ 1 #include <iostream> 2 using namespace std; 3 int main() 4 { 5 int num1; // to hold the first value 6 int num2; // to hold the second value 7 int result; // to hold the result /* read the two integer values */ 8 cout << endl << Enter two integer values, please: ; 9 cin >> num1; 10 cin >> num2; /* compute their sum and print the result */ 11 result = num1 + num2; 12 cout << endl << Atheir sum is:@ << result; 13 return 0; 14 } 2. a. char grade; a memory location to hold a character will be created. It will be identified by the name grade. b. int idnum; a memory location to hold an integer value will be created. It will be identified by the name idnum. 3. Good job num= 9 sum= 14 num= 7 sum= 12

4 Solution Exercise 1.5 A. The order of execution is: 10, 11, 12, 4, 5, 6, 7, 13, 14, 15. B. The output is as follows: result1 = 7 result2 = 16 Solution Exercise 1.6 the contents of the file myprog.cpp after it has been processed by the preprocessor is as follows: /* my program file */ /* my header file */ int flag = 0; void tfun( int ); // to perform some tasks int process( int ); /* That=s all */ Solution Exercise 1.7 int main() { int number, sum; number = 16; sum = number - process( number ); tfun( number ); return ( 0 ); } 1. The output is a follows: The result is: 25 The result is: 16 2.

5 Line # Statements/Comments 1. // This is a sample program 2 // It reads integer values, performs some computations 3 and prints the results. 4 #include <iostream> 5 using namespace std; 6 int main( ) 7 { 8 int num1; 9 int num2 = 3; 10 int result1; 11 int result2; 12 cin >> num1; 13 result1 = num1 + 5; /* compute the sum of the value read and 5 */ 14 result2 = num2 + 5; 15 cout << endl << result1 = 16 << result1; 17 num1 = num1 + 10; 18 num2 + 7 = num1; 19 cout << num1; 20 << result1; 21 cout << 15; 22 cin >> num2 + 3; 23 result3 = num1 + 25; 24 return (0); 25 } Line 3 is invalid: a comment must be preceded by // or enclosed between the characters /* and */ Line 18 is invalid: you can specify only a variable/memory location on the left-hand side of the assignment operator. Line 20 is invalid: there is a semicolon at the end of line 19. Line 22 is invalid: only a variable/memory location can appear in a cin statement. Line 23 is invalid: variable result3 is not declared. Solution Exercise 1.9 Fill in the blanks with the most appropriate answers. 1. A memory location is a portion of the main memory that is used to represent (hold) data. 2. A compiler is a system program that translates a high-level language program into machine language. 3. An object file (module) is created by the compiler to hold the machine language translation of a source file. 4. An interpreter receives as input the statements of a program and its input data, executes the statements of that program using its input data, and produces its output. 5. In a high-level language program, a memory location is represented by a variable. 6. The data type of a variable tells to the compiler the type of data that will be stored in the corresponding memory location, so that it knows how many bytes to reserve for that memory location. 7. In a high-level language program, a comment is a note or a remark for a human being reading the program, and is ignored by the compiler. 8. A high-level language program consists of one or more files called source files.

6 9. A function has a name and consists of a sequence of one or more statements used to perform a specific task. 10. A library function is a function that comes with the compiler, and that can be called in any program. 11. The preprocessor is a program that first processes and completes a program source file before it is translated into machine language by the compiler. 12. The linker combines all the object modules of a program and the machine language translations of library functions called in the program in a file called executable file.