匹配被4整除的数字的正则表达式是什么? [英] What is a regular expression for matching numbers divisible by 4?

问题描述

我想制作一个词法分析器来检测被4整除的数字.
示例代码-

I want to make a lexical analyzer that detects numbers divisible by 4.
Sample code -

%%
16(divisible by 4) {printf("divisible by 4 %s\n",yytext);}
%%
main()
{
        yylex();
}

推荐答案

%%  
[0-9]+  {int number = atoi(yytext); if((number % 4) == 0) printf("Div_4 %d\n", number);}
%%

main()
{
        yylex();
}

由于lex/flex支持C，因此您可以将字符串另存为整数，然后在C中进行检查.

As lex/flex support C, so you can save the string as integer and then check it in C.

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