strlen

C++11 char16_t strlen-equivalent function

由 自作多情 提交于 2019-12-10 02:09:31
问题 I have a simple question: Is there a way to do a strlen() -like count of characters in zero-terminated char16_t array? 回答1: use char_traits<char16_t>::length(your_pointer) see 21.2.3.2 struct char_traits<char16_t> and table 62 of the C++11-Std. 回答2: Use pointers :), create a duplicate pointer to the start, then loop through it while (*endptr++); , then the length is given by endptr - startptr . You can actually template this, however, its possible the the compile won't generate the same

strlen() php function giving the wrong length of unicode characters [duplicate]

由 冷暖自知 提交于 2019-12-09 15:54:14
问题 This question already has answers here : PHP: strlen returns character length instead of byte length (4 answers) Closed 6 years ago . I am trying to get the length of this unicode characters string $text = 'نام سلطان م'; $length = strlen($text); echo $length; output 20 How it determines the length of unicode characters string? 回答1: strlen() is not handling multibyte characters correctly, as it assumes 1 char equals 1 byte, which is simply invalid for unicode. This behavior is clearly

Create my own strlen and substring functions

由 99封情书 提交于 2019-12-08 14:20:15
问题 I am trying to create my own strlen and substr functions and I have 1 problem. for example, let say I have the string ABC, my strlen will return 3, let say I want to cut this string from 0 to 1 its should return to me A,but I get some trash values, if I insert the substr to a new char and check the length I will recieve 14. this is my code: int len(char *w){ int count=0; int i=0; while (w[i]!='\0') { count++; i++; } //cout<<"Length of word is:"<<count<<"\n"; return count; } char *subs(char *w

C string from GetString() when strlen produces segmentation fault [closed]

由 此生再无相见时 提交于 2019-12-08 13:20:23
问题 This question is unlikely to help any future visitors; it is only relevant to a small geographic area, a specific moment in time, or an extraordinarily narrow situation that is not generally applicable to the worldwide audience of the internet. For help making this question more broadly applicable, visit the help center. Closed 6 years ago . I am running a program in C. When I run the program I get a segmentation fault error. IN gdb when I backtrace it tells me Program received signal SIGSEGV

php mb_strlen return value is weird [closed]

由 这一生的挚爱 提交于 2019-12-08 09:45:50
问题 This question is unlikely to help any future visitors; it is only relevant to a small geographic area, a specific moment in time, or an extraordinarily narrow situation that is not generally applicable to the worldwide audience of the internet. For help making this question more broadly applicable, visit the help center. Closed 7 years ago . gb2312 is a double byte character set, using mb_strlen() to check a single chinese character will return 2, but for 2 more characters,sometimes the

Checking string length, max and minimum

由 我的梦境 提交于 2019-12-08 03:40:22
问题 Is there a function to check if a string is too long or too short, I normally end up writing something like this in several places: if (strlen($input) < 12) { echo "Input is too short, minimum is 12 characters (20 max)."; } elseif(strlen($input) > 20) { echo "Input is too long, maximum is 20 characters."; } I know you can easily write one but is there one built into PHP? I normally collect errors as I validate input, so the above code would be written: $errors = array(); if (strlen($input) <

Different ways to calculate string length

由 徘徊边缘 提交于 2019-12-07 18:04:46
问题 A comment on one of my answers has left me a little puzzled. When trying to compute how much memory is needed to concat two strings to a new block of memory, it was said that using snprintf was preferred over strlen, as shown below: size_t length = snprintf(0, 0, "%s%s", str1, str2); // preferred over: size_t length = strlen(str1) + strlen(str2); Can I get some reasoning behind this? What is the advantage, if any , and would one ever see one result differ from the other? 回答1: I was the one

php--------使用 isset()判断字符串长度速度比strlen()更快

由 主宰稳场 提交于 2019-12-07 10:32:07
isset()速度为什么比strlen()更快呢？ strlen()函数函数执行起来相当快，因为它不做任何计算，只返回在zval 结构(C的内置数据结构，用于存储PHP变量)中存储的已知字符串长度。但是，由于strlen()是函数，多多少少会有些慢，因为函数调用会经过诸多步骤，如字母小写化、哈希查找，会跟随被调用的函数一起执行。因此在某些情况下，合理使用isset()可以加速你的程序。因为isset()是一种语言结构，它的执行不需要函数查找和字母小写化等。 具体通过 isset() 和 strlen() 判断字符串长度示例如下： $str='http://www.phpernote.com/php-template/436.html'; if(strlen($str)<5){echo "未满5";} if(!isset($str{5})){echo "未满5";} 下面我们来详细的分析一下strlen()和isset()这两个函数。 PHP strlen() 函数 定义和用法 strlen() 函数返回字符串的长度。 语法：strlen(string) 参数：string 描述：必需。规定要检查的字符串。 strlen() 函数实例 <?php echo strlen("Hello world!"); ?> 结果将输出： 12 PHP isset() 函数

strlen not giving correct string length C

由 。_饼干妹妹 提交于 2019-12-07 02:13:39
问题 I am reading from my dictionary and printing out the word + the length of the word for testing purposes. I use strlen to get the length of the string. However, the numbers I got are not correct. I believe strlen doesn't count the \0 character. I am reading the first 10 words in the dictionary. My expected output should be: W:A L:1 W:A's L:3 W:AA's L:4 W:AB's L:4 W:ABM's L:5 W:AC's L:4 W:ACTH's L:6 W:AI's L:3 W:AIDS's L:6 W:AM's L:4 But this is what I got (Notice how the L:'s are on another

Does strlen return same value for a binary and ascii data

由 隐身守侯 提交于 2019-12-06 15:33:38
问题 Please find the below code snippet. unsigned char bInput[20]; unsigned char cInput[20]; From a function, I get a binary data in bInput and I determined its length using strlen(bInput) . I converted bInput which is in binary to ASCII and stored in cInput and printed its length. But both are different. I am new to programming. Please guide regarding its behaviour. 回答1: result wont be same for both cases. Below is one sample scenario: Null is valid UTF-8, it just doesn't work with C 'strings'.
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