#include <iostream>

int main()

{

    std::string str("   字符串   String    ");

    std::cout << str << std::endl;

    std::cout << str.size() << std::endl;

    str.erase(str.find_first_of(' '), str.find_first_not_of(' '));

    str.erase(str.find_last_not_of(' ') + );

    std::cout << str << std::endl;

    std::cout << str.size() << std::endl;

    return ;

}

#include <stdio.h>

#include <string.h>

#define STRING_LENGTH 10000

int main()

{

    const char *text = "   字符串   String    ";

    printf("%s\n%u\n", text, strlen(text));

    while (*text == ' ')

        ++text;

    char str[STRING_LENGTH];

    strcpy(str, text);

    size_t i = strlen(str) - ;

    while (str[i] == ' ')

        str[i--] = '\0';

    printf("%s\n%u\n", str, strlen(str));

    return ;

}

g++ -std=c++11 StdStringTrimTest.cpp -o StdStringTrimTest

gcc -std=c11 CStyleStringTrimTest.c -o CStyleStringTrimTest