(PPT)计算机专业英语.pptVIP

Computer English Chapter 7 Programming language Every language must have instructions that fall into the following familiar categories. (1)Input/Output instructions.Required to permit communication between I/O devices and the central processor,these instructions provide details on the type of input or output operation to be performed and the storage locations to be used during the operation. (2)Calculation instructions.Instructions to permit addition,subtraction,multiplication,and division during processing are,of course,common in all programming languages. (3)Logic/comparison instruction.These instructions are used to transfer program control,and are needed in the selection and loop structures that are followed to prepare programs.During processing ,two data items may be compared as a result of the execution of logic instruction.As you know,program control can follow different paths depending on the outcome of a selection test(if r0 then A,else B). (4)Storage/retrieval and movement instructions.These instructions are used to store,retrieve,and move data during processing. Machine languages A computer’s machine language consists of strings of binary numbers and is the only one the CPU directly “understand”.An instruction prepared in any machine language will have at least two parts.The first part is the command or operation,and it tells the computer what function to perform.The second part of the instruction is the operand,and it tells the computer where to find or store the data or other instructions that are to be manipulated. C++ fully supports object-oriented programming,including the four pillars of object-oriented development:encapsulation,data hiding,inheritance,and polymorphism. When an engineer needs to add a resistor to the device he is creating,he doesn’t typically build a new one from scratch.He walks over to a bin of resistors and examines the properties,and picks the one he needs.The resistor is a “black box” as far as the engine