如何在字典上比较两个字符串向量？

Question

I am doing a C++ exercise where I have to implement a class representing a weak version of a vector that holds a string. One of the requirements is to overload the < and > operator following the rules of lexographical comparison.

I've been reading up on the algorithm but I don't understand it at all or how to implement it. What makes a vector < than the other? What do I compare from the strings? The private variables are string *array, size, and capacity.

Answer 1

You can use strcmp(string a, string b) in '<' overloading implementation.

class ClassName{
  /*
  variables

  constructors and methods
  */

  bool operator<(ClassName obj){
    ClassName obj1;
    if(strcmp(obj.str , obj1.str)<0)  //less than zero as we are overloading "<" operator
      return true;     //read - www.cplusplus.com/reference/cstring/strcmp

    return false;
  }
};

Similarly the ">" operator can be overloaded

Answer 2

The idea of a lexographical comparison between two sequences is that you sort the sequences first by their first element, and if necessary then by their second, etctera. That is to say, if a[0]<b[0] then a<b . If a[0]>b[0] , then a>b . But if a[0]==b[0] , then you look at a[1] and b[1] .

When the sequence is a sequence of characters (aka string), this is the common dictionary order. But the same algorithm works on any sequence of sortable elements.