C语言 #define do while
Webdo { // code } while (false) ; The do/while can create a scope, thus encapsulating the macro's code, and needs a semi-colon in the end, thus expanding into code needing one. The bonus? The C++ compiler will optimize away the do/while loop, as the fact its post-condition is false is known at compile time. This means that a macro like: WebDec 18, 2024 · #define identifier token-sequence The preprocessor runs before the compiler transforms your code for use in the compiler. The order is as follows: Trigraph replacement Line splicing Macro definition and expansion So with the #define you can have character manipulation (macro substitution). Whenever M is seen 4 will be substituted.
C语言 #define do while
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WebJan 12, 2011 · #define STUFF () \ { do_something (); do_something_else (); } if (cond) STUFF (); else //... the extra semi-colon breaks the syntax. The do {} while (false) instead is a single statement. You can find more about this and other macro tricks here. Share Improve this answer Follow answered Jan 12, 2011 at 22:10 Giuseppe Ottaviano 4,493 2 18 18 7 Webdo while循环,C语言do while循环详解 一套完整的嵌入式开发学习路线(高薪就业版),知识全面,思路清晰,猛击这里免费领取! do…while 循环不经常使用,其主要用于人机 …
Web在C语言的宏中,#的功能是将其后面的宏参数进行字符串化操作(Stringfication),简单说就是在对它所引用的宏变量通过替换后在其左右各加上一个双引号。 比如下面代码中的宏: 1. #使用 #define WARN_IF (EXP) / do { if (EXP) / fprintf (stderr, "Warning: " #EXP "/n"); } / while (0) 那么实际使用中会出现下面所示的替换过程: WARN_IF (divider ); 其中divider … Web在 C 语言中, do...while 循环是在循环的尾部检查它的条件。 do...while 循环与 while 循环类似,但是 do...while 循环会确保至少执行一次循环。 语法 C 语言中 do...while 循环 …
WebApr 1, 2024 · 今天我们来说我们的do…while循环,其实这个循环和我们的while循环很像,区别就在于我们现在要学的这个循环是先执行一次循环,再去判断条件是否正确。. … http://c.biancheng.net/view/187.html
WebC/C++语言中的宏定义技巧 ... #ifdef DEBUG #define DEBUG_PRINT(x) printf x #else #define DEBUG_PRINT(x) do {} while (0) #endif. 这段代码的意思是,如果定义了DEBUG宏,那么就使用printf函数输出调试信息。否则,就使用一个空语句块来忽略这个宏。
WebApr 11, 2024 · 上一期咱们用c语言实现了三子棋的小游戏 c语言实现三子棋 今天我们再来写个扫雷的游戏,说起扫雷,相信大家都不陌生,可能许多朋友还是玩扫雷的高手。 其实扫雷和三子棋有许多相似之处,都需要用到数组的知识。 grade 9 annotated macbethWebWhy are there sometimes meaningless do/while and if/else statements in C/C++ macros? I met code like below: #define ev_io_init(ev,cb,fd,events) \ do { \ ev_init ((ev), (cb)); \ … chiltern secondary schoolhttp://c.biancheng.net/view/181.html grade 9 analysis of remainsWeb表达式(_LINE_==-1)为假。 此宏定义使用do { }while ( )结构避免了在引用宏定义时的错误。 示例: 正确形式: #define SET_REGS () st ( ioreg1 = 0; ioreg2 = 0; ) 不正确的格式分析: 1、#define SET_REGS () ioreg1 = 0; ioreg2 = 0; 此宏定义在使用if、else格式时会报错。 eg: if ( 条件) SET_REGS () else {} 错误原因:if-else没有接上,在SET_REGS ()需加 {} … grade 9 algebra worksheets with answers pdfWebDec 17, 2024 · 通常在C编程语言中,1定义为true,0定义为false . 因此,为什么你经常看到以下内容: #define TRUE 1 #define FALSE 0 但是,在条件语句中,任何不等于0的数字都将被计算为true . 因此使用以下内容: #define TRUE (1==1) #define FALSE (!TRUE) 你可以明确地表明你试图通过使虚假等于任何不真实的东西来安全地发挥它 . 回复于 2024-12 … grade 9 an inspector calls analysishttp://c.biancheng.net/view/1980.html grade 9 assignment term 1WebA do {}while (0) allows you to break from the loop: do { expr1; foo (); if ( cond ) break; expr2; goo (); } while (0); It's the same as a simple block {...} except that you can break execution when you want with the break statement. You couldn't do that in a simple code block, unless you have multiple checks, which can get cumbersome. grade 9 atp technology 2022