使用4种方法来算字符串长度

str::strlen,

string::length,

loop操作,

形式语言的标准递归。

 

#include <cstdio> #include <string> #include <cstring> #include <iostream> using namespace std; int strlen_by_loop( char* const psz ) { char* p = psz; int iLen = 0; while( *p++ ) iLen++; return iLen; }// int strlen_by_recusive( char* const psz ) { if( *psz == '/0' ) return 0; else return strlen_by_recusive( psz + 1 ) + 1; }// int main() { char* psz = "hello,world"; string str( psz ); cout<<"Length of 'hello,world' by 'std::strlen()' = "<<strlen( psz )<<endl <<"Length of 'hello,world' by 'string::length()' = "<<str.length()<<endl <<"Length of 'hello,world' by 'strlen_by_loop' = "<<strlen_by_loop( psz )<<endl <<"Length of 'hello,world' by 'strlen_by_recusive' = "<<strlen_by_recusive( psz )<<endl<<endl; return 0; }//