strlen

• Returns the length of the C string str.
• The length of a C string is determined by the terminating null-character: A C string is as long as the number of characters between the beginning of the string and the terminating null character (without including the terminating null character itself).
• 返回給定空終止字符串的長度，即首元素為 str 所指，且不包含首個空字符的字符數組中的字符數。
• 計算字符串 str 的長度，直到空結束字符，但不包括空結束字符。

• 若 str 不是指向空終止字節字符串的指針則行為未定義。

  size_t strlen( const char *str );

Parameters

str

• C string.
• 要計算長度的字符串。

Return Value

• The length of string.
• 該函數返回字符串的長度。

Example

//
// Created by zhangrongxiang on 2018/2/7 10:41
// File strlen
//
 


#include <stdio.h>
#include <string.h>

//Software is like sex: it"s better when it"s free.
//My name is Linus, and I am your God
//Linux is obsolete.
//Linux is not Unix

int main() {
    char *str = "My name is Linus, and I am your God";
    size_t length = strlen(str);
    printf("%s --> length is %d
 
\n", str, (int) length);

    char *str2 = "一切皆文件";
    length = strlen(str2);
    printf("%s  -- length --> %d\n", str2, (int) length); //15 = 3 * 15
    printf("%s  -- sizeof --> %d\n", str2, (int) sizeof("一切皆文件")); //16 = 3 * 5 + 1

    char str3[] = "萬物皆對象";
    printf("%s  -- sizeof --> %d\n", str3, (int) sizeof(str3)); //16 = 3 * 5 + 1

    return 0;
}

文章參考

• http://zh.cppreference.com/w/c/string/byte/strlen
• http://www.cplusplus.com/reference/cstring/strlen/
• http://www.runoob.com/cprogramming/c-function-strlen.html

轉載註明出處

C 標準庫 - string.h之strlen使用