这是我想到的:

std::stringstream trimmer;
trimmer << str;
trimmer >> str;

流提取自动消除空白，所以这就像一个魅力。 要我说的话，也相当干净优雅。；）

For what it's worth, here is a trim implementation with an eye towards performance. It's much quicker than many other trim routines I've seen around. Instead of using iterators and std::finds, it uses raw c strings and indices. It optimizes the following special cases: size 0 string (do nothing), string with no whitespace to trim (do nothing), string with only trailing whitespace to trim (just resize the string), string that's entirely whitespace (just clear the string). And finally, in the worst case (string with leading whitespace), it does its best to perform an efficient copy construction, performing only 1 copy and then moving that copy in place of the original string.

void TrimString(std::string & str)
{ 
    if(str.empty())
        return;

    const auto pStr = str.c_str();

    size_t front = 0;
    while(front < str.length() && std::isspace(int(pStr[front]))) {++front;}

    size_t back = str.length();
    while(back > front && std::isspace(int(pStr[back-1]))) {--back;}

    if(0 == front)
    {
        if(back < str.length())
        {
            str.resize(back - front);
        }
    }
    else if(back <= front)
    {
        str.clear();
    }
    else
    {
        str = std::move(std::string(str.begin()+front, str.begin()+back));
    }
}

C++11：

int i{};
string s = " h e ll \t\n  o";
string trim = " \n\t";

while ((i = s.find_first_of(trim)) != -1)
    s.erase(i,1);

cout << s;

输出:

hello

也适用于空字符串

我喜欢tzaman的解决方案，唯一的问题是它不修剪只包含空格的字符串。

为了纠正这1个缺陷，在2个微调行之间添加str.clear()

std::stringstream trimmer;
trimmer << str;
str.clear();
trimmer >> str;

我用的是这个:

void trim(string &str){
    int i=0;

    //left trim
    while (isspace(str[i])!=0)
        i++;
    str = str.substr(i,str.length()-i);

    //right trim
    i=str.length()-1;
    while (isspace(str[i])!=0)
        i--;
    str = str.substr(0,i+1);
}

下面是一个简单的实现。对于这样一个简单的操作，您可能不应该使用任何特殊的构造。内置的isspace()函数负责处理各种形式的白色字符，因此我们应该充分利用它。您还必须考虑字符串为空或只是一堆空格的特殊情况。向左或向右修剪可以从下面的代码派生。

string trimSpace(const string &str) {
   if (str.empty()) return str;
   string::size_type i,j;
   i=0;
   while (i<str.size() && isspace(str[i])) ++i;
   if (i == str.size())
      return string(); // empty string
   j = str.size() - 1;
   //while (j>0 && isspace(str[j])) --j; // the j>0 check is not needed
   while (isspace(str[j])) --j
   return str.substr(i, j-i+1);
}