Address: http://www.ibm.com/developerworks/cn/rational/r-usecase-atm/index.html
Level: elementary
Fu chunyi, technical sales manager of Rational China, software department of IBM China Co., Ltd.
November 01, 2004
Use Case is a method used to
Case modeling GuideFu chunyi, technical sales manager of rational China, software department of IBM China Co., Ltd.November 01, 2004Original URL: http://www-128.ibm.com/developerworks/cn/rational/r-usecase-atm/@
Use case is a method used to describe system requirements. The process of describing system requirements using use cases is case modeling. The use case method was first proposed by Dr. IVA jackboson and was later integrated into the UML
1. Define (that is, host variable)The main role of the host variable is to act as an alternative variable, a medium in which the host environment can interact with Oracle . When you define a host variable by define, you must specify the variable
The difference between #define, const, typedef#define is not defining variables, it's just for text substitution.For example:#define PI 3.1415926float Angel;angel=30*pi/180;Then, when the program is compiled, the compiler will first "#define PI 3.141
#define是C语言中提供的宏定义命令, the main purpose is to provide programmers with certain convenience in programming, and to a certain extent, improve the efficiency of the program, but students often do not understand the nature of the command in learning,
There are many places in the C language where macro definitions are used, such as in header files to prevent header files from being repeatedly included:
#ifndef ctest_header_h
#define CTEST_HEADER_H
/header file content
#endif
Many macro
1.c Language switch/case defines the variable case 0:int b = 0; printf ("0"), Break;case 1:printf ("1"), break;default:printf ("Default"); C and C + + will error 1: case0:int B; b = 0; printf ("0"), Break;case 1:printf ("1"), break;default:printf
#define是C语言中提供的宏定义命令, the main purpose is to provide programmers with certain convenience in programming, and to a certain extent, improve the efficiency of the program, but students often do not understand the nature of the command in learning,
As we all know, in PHP (PHP 4 and later), we can use the function define () to define constants, for example:
However, after PHP 5.3.0, in addition to using function define (), we can also use the PHP keyword const to define constants.
For example:
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