boost::trim 在 C++ 库中

该函数包含在“boost/algorithm/ 字符串”库中。 Boost 字符串算法库提供了 STL 中缺少的字符串相关算法的通用实现。修剪函数用于从字符串删除所有前导或尾随空格。输入序列就地修改。

• trim_left()：从字符串删除所有前导空格。
• trim_right()：从字符串删除所有尾随空格。
• trim()：从字符串删除所有前导和尾随空格。

句法：

Template:
trim(Input, Loc);

Parameters:
Input: An input sequence
Loc: A locale used for ‘space’ classification

Returns: The modified input sequence without leading or trailing white spaces.

例子：

Input: ”    geeks_for_geeks    ” 
Output: Applied left trim: “geeks_for_geeks    ” 
Applied right trim: ”    geeks_for_geeks” 
Applied trim: “geeks_for_geeks” 
Explanation: 
The trim_left() function removes all the leading white spaces.
The trim_right() function removes all the trailing white spaces.
The trim() function removes all the leading and trailing white spaces.

下面是使用函数boost::trim()从字符串删除空格的实现：

C++

// C++ program to remove white spaces
// from string using the function
// boost::trim function
#include 
#include 
using namespace boost::algorithm;
using namespace std;
  
// Driver Code
int main()
{
    // Given Input
    string s1 = "    geeks_for_geeks    ";
    string s2 = "    geeks_for_geeks    ";
    string s3 = "    geeks_for_geeks    ";
  
    // Apply Left Trim on string, s1
    cout << "The original string is: \""
         << s1 << "\" \n";
    trim_left(s1);
    cout << "Applied left trim: \""
         << s1 << "\" \n\n";
  
    // Apply Right Trim on string, s2
    cout << "The original string is: \""
         << s2 << "\" \n";
    trim_right(s2);
    cout << "Applied right trim: \""
         << s2 << "\" \n\n";
  
    // Apply Trim on string, s3
    cout << "The original string is: \""
         << s3 << "\" \n";
    trim(s3);
    cout << "Applied trim: \"" << s3
         << "\" \n";
  
    return 0;
}

输出：

The original string is: "    geeks_for_geeks    " 
Applied left trim: "geeks_for_geeks    " 

The original string is: "    geeks_for_geeks    " 
Applied right trim: "    geeks_for_geeks" 

The original string is: "    geeks_for_geeks    " 
Applied trim: "geeks_for_geeks"

时间复杂度： O(N)
辅助空间： O(1)

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