Step by Step solution about How to resolve the algorithm Substring step by step in the C++ programming language

The provided C++ code demonstrates the use of the substr() method of the string class to extract substrings from a given string. Here's a detailed explanation of each operation:

• s.substr(n, m): This line extracts a substring from the string s starting at position n (inclusive) and continuing for m characters. In this case, it extracts the substring starting at position n=3 and continuing for m=4 characters, which results in "4567".

• s.substr(n): This line extracts a substring from the string s starting at position n (inclusive) and continuing until the end of the string. In this case, it extracts the substring starting at position n=3, which results in "456789".

• s.substr(0, s.size()-1): This line extracts a substring from the string s starting at position 0 (inclusive) and continuing for s.size() - 1 characters. This effectively removes the last character from the string, resulting in "01234568".

• s.substr(s.find(c), m): This line extracts a substring from the string s starting at the first occurrence of the character c and continuing for m characters. In this case, it looks for the character '2' in the string s, finds it at position 2, and extracts the substring starting from there and continuing for m=4 characters, which results in "2345".

• s.substr(s.find(sub), m): Similar to the previous line, this line extracts a substring from the string s starting at the first occurrence of the substring sub and continuing for m characters. In this case, it looks for the substring "456" in the string s, finds it at position 3, and extracts the substring starting from there and continuing for m=4 characters, which results in "4567".

The output of the program will be:

4567
456789
01234568
2345
4567

#include <iostream>
#include <string>

int main()
{
  std::string s = "0123456789";

  int const n = 3;
  int const m = 4;
  char const c = '2';
  std::string const sub = "456";

  std::cout << s.substr(n, m)<< "\n";
  std::cout << s.substr(n) << "\n";
  std::cout << s.substr(0, s.size()-1) << "\n";
  std::cout << s.substr(s.find(c), m) << "\n";
  std::cout << s.substr(s.find(sub), m) << "\n";
}