strlen | 易学教程

PHP: strlen returns character length instead of byte length

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问题 I have a wordpress web site. I've created simple page template like: <?php /** * Template Name: Test */ echo strlen('Привет'); ?> Then i've created a page using this template. The page shows the length of russian string 'Привет' (means 'Hello'). I expect to see 12, as UTF-8 encoded russian string consisting of 6 characters should have a size of 12 bytes, but i get 6 instead. I've tested the same thing on other server and had correct value - 12. So i think the reason is my server configuration

Why can't I get the length of the whole string?

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问题 I tried strlen(string). And I tried writing the code for finding the length of the whole string. However it still tends to stop counting the length when the first 'space' is reached. Why does it happen? What is the solution? I'm trying to stop at '\0'. Shouldn't this work? Here is the part of the code. int main(void) { char phrase[256]; char phrase2[256]; int i,j,size; scanf("%255s", phrase); for(i=0;phrase[i]!='\0';i++){ size++; } ... 回答1: The reason it stops counting is because scanf reads

how does strlen count unicode in c

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问题 I'm curious as to how strlen count unicode characters of multiple bytes in C. Does it count each byte or character (as they can consist of several bytes) until first '\0'? 回答1: strlen() counts number of bytes until a \0 is encountered. This holds true for all strings. For Unicode, note that the return value of strlen() may be affected by the possible existing \0 byte in a valid character other than the null terminator. If UTF-8 is used, it's fine because no valid character other than ASCII 0

sizeof与strlen的区别

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sizeof是一个关键字不是函数，发生在编译时刻。 sizeof是C/C++中的一个运算符，其作用是返回一个对象或者类型在内存中所占用的字节数。注意：sizeof后面如果是类型则必须加括号，如 sizeof(char)；而如果是变量名则可以不加括号，如 sizeof a; 但是建议使用时均加上括号。sizeof不能返回动态地被分配的数组的大小。总结如下，当参数分别如下时，sizeof返回的值表示的含义如下：数组——编译时分配的数组空间大小；指针——存储该指针所用的空间大小（在32位系统是4，在64系统是8）；类型——该类型所占的空间大小；对象——对象的实际占用空间大小；函数——函数的返回类型所占的空间大小。函数的返回类型不能是void strlen是C语言中的库函数，发生在运行时刻，所在头文件为#include <string.h>其函数原型为unsigned int strlen(char *s); 其中s为指定的字符串。注意：strlen只能用char *作为参数，它求的是字符串的实际长度，方法是从开始到遇到第一个'\0'结束。 sizeof只关心这块内存的大小，不关心这块内存存放了什么数据， strlen只关心这块内存存放的数据，不关心这块内存的大小，直到遇到第一个NULL为止。二、几个例子例1： char str[20] = "0123456789";

Where is the implementation of strlen() in GCC?

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问题 Can anyone point me to the definition of strlen() in GCC? I've been grepping release 4.4.2 for about a half hour now (while Googling like crazy) and I can't seem to find where strlen() is actually implemented. 回答1: You should be looking in glibc, not GCC -- it seems to be defined in strlen.c -- here's a link to strlen.c for glibc version 2.7... And here is a link to the glibc SVN repository online for strlen.c. The reason you should be looking at glibc and not gcc is: The GNU C library is

How do I use strlen() on a formatted string?

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问题 I'd like to write a wrapper function for the mvwprint/mvwchgat ncurses functions which prints the message in the specified window and then changes its attributes. However, mvwchgat needs to know how many characters it should change - and I have no idea how to tell mvwchgat how long the formatted string is, since a strlen() on, for instance, "abc%d" obviously returns 5, because strlen doesn't know what %d stands for ... 回答1: In C99 or C11, you can use a line like this: length = snprintf(NULL,

strlen function using recursion in c

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问题 I'm kida new to the recursion subject and i've been trying to write the "strlen" function using recurion, thats what i tried: int strlen ( char str[], int i) { if ( str[i] == 0) return i+1; return strlen(str,i++); } and i tried something very similiar int strlen( char str[], int i) { if ( str[i] == 0) return 1; return strlen(str,i++) + 1; } and in my main function int main() { char word[MAX_DIGITS]; scanf("%s",word); printf("%d", strlen(word,0)); return 0; } but my program would crash

sizeof和strlen的区别

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1. sizeof操作符的结果类型是size_t，它在头文件中的typedef为unsigned int类型。该类型保证能容纳实现所建立的最大对象的字节大小。 2. sizeof是算符，strlen是函数。 3. sizeof可以用类型做参数，strlen只能用char*做参数，且必须是以“\0”结尾的。sizeof还可以用函数做参数，比如： short f();printf("%d\n", sizeof(f())); 输出结果是sizeof(short)，即2。 4. 数组做sizeof的参数不退化，传递给strlen就退化为指针。 5. 大部分编译程序在编译的时候就把sizeof计算过了，是类型或是变量的长度。这就是sizeof(x)可以用来定义数组维数的原因： char str[20] = "0123456789";int a = strlen(str); // a=10int b = sizeof(str); // b=20 6. strlen的结果要在运行的时候才能计算出来，用来计算字符串的长度，而不是类型占内存的大小。 7. sizeof后如果是类型必须加括号，如果是变量名可以不加括号。这是因为sizeof是个操作符而不是个函数。 8. 当使用了一个结构类型或变量时，sizeof返回实际的大小。当使用一静态的空间数组时，sizeof返回全部数组的尺寸

sizeof与strlen的不同

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sizeof操作符的结果类型是size_t，它在头文件中typedef为unsigned int类型。该类型保证能容纳实现所建立的最大对象的字节大小。 sizeof是算符，strlen是函数。 sizeof可以用类型做参数，strlen只能用char*做参数，且必须是以''\0''结尾的。 sizeof还可以用函数做参数，比如： short f(); printf("%d\n", sizeof(f())); 输出的结果是sizeof(short)，即2。数组做sizeof的参数不退化，传递给strlen就退化为指针了。大部分编译程序在编译的时候就把sizeof计算过了是类型或是变量的长度这就是sizeof(x)可以用来定义数组维数的原因 char str[20]="0123456789"; int a=strlen(str); //a=10; int b=sizeof(str); //而b=20; strlen的结果要在运行的时候才能计算出来，时用来计算字符串的长度，不是类型占内存的大小。 sizeof后如果是类型必须加括弧，如果是变量名可以不加括弧。这是因为sizeof是个操作符不是个函数。当适用了于一个结构类型时或变量， sizeof 返回实际的大小，当适用一静态地空间数组， sizeof 归还全部数组的尺寸。 sizeof

PAT(A)1031 Hello World for U (20分)

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Sample Input helloworld ! Sample Output h ! e d l l lowor 思路：模拟就好。代码： # include <stdio.h> # include <string.h> char a [ 101 ] ; int main ( ) { gets ( a ) ; int k = ( strlen ( a ) + 2 ) / 3 ; int t = strlen ( a ) - 2 * k + 2 ; for ( int i = 0 ; i < k - 1 ; ++ i ) { printf ( "%c" , a [ i ] ) ; for ( int j = 0 ; j < t - 2 ; ++ j ) printf ( " " ) ; printf ( "%c" , a [ strlen ( a ) - 1 - i ] ) ; printf ( "\n" ) ; } for ( int i = 0 ; i < t ; ++ i ) printf ( "%c" , a [ k + i - 1 ] ) ; //getchar();getchar(); return 0 ; } 来源： CSDN 作者： ssqsssq 链接： https://blog.csdn.net/weixin_43778744/article/details

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