c++ - 控制台输出线的宽度限制

Question

Class 向控制台打印一个字符串。 如何使输出行的宽度等于 characterWidth = 40, 即在 40 个字符被转移到一个新行之后？

#include <string>
#include <iostream>

class StringProcessing {
  public:
      StringProcessing() : characterWidth(40),
                     textToBeFormatted("NULL") {}

      inline void StringProcessing::initString() {
          textToBeFormatted =
              "text    some text   some text some text   some text some text"
              "text some text  some text    some text some text some text"
              "text    some      text some    text some   text some text"
              "text some  text some    text some    text some text some text"
              "text   some     text some text some   text some text some text";
      }

      inline void displayString()
        { std::cout << textToBeFormatted << std::endl; }
  private:    
      int characterWidth;
      std::string textToBeFormatted;
};

我有一个想法但是这里console中的字被截断了，所以需要调到下一行进行宽度对齐

inline void displayString()
      {
         const std::string& s = textToBeFormatted;
         for (int i = 0; i < s.length() / 40 + (bool)(s.length() % 40); ++i)
         {
            std::cout << std::left
                      << std::setfill(' ')
                      << std::setw(40)
                      << s.substr(i * 40, 40)
                      << std::endl;
         }
      }

Answer 1

这是适合我的答案

#include <string>
#include <iostream>
#include <iomanip>

class StringProcessing
{
public:
    StringProcessing() : characterWidth(40),
        textToBeFormatted("NULL") {}

    inline void initString() {
        textToBeFormatted = "text    some text   some text some text   some text some text"
            "text some text  some text    some text some text some text"
            "text    some      text some    text some   text some text some text"
            "text some  text some    text some    text some text some text"
            "text   some     text some text some   text some text some text";
    }

    inline void displayString()
    {
        const std::string& s = textToBeFormatted;
        const int& width = characterWidth;
        for (int current = 0; current < s.length();)
        {
            if (s.length() < width)
            {
                output(s);
                break;
            }
            if (s.length() - current < width)
            {
                output(s.substr(current));
                break;
            }
            std::string substr = s.substr(current, width);
            current += width;
            size_t space = substr.rfind(' ');
            if (space != std::string::npos && (substr[width - 1] != ' ' &&
                (s.length() > current && s[current] != ' ')))
            {
                current -= width - space - 1;
                substr = substr.substr(0, space + 1);
            }
            output(substr);
        }
    }
private:
    inline void output(const std::string& s)
    {
        std::cout << setfill(' ') << std::right << std::setw(characterWidth) << s << std::endl;
    }
    int characterWidth;
    std::string textToBeFormatted;
};