Step by Step solution about How to resolve the algorithm Determine if a string is collapsible step by step in the C++ programming language

The provided C++ code demonstrates a function called collapse that removes consecutive duplicate characters from a string and some sample usage to test the function. Here's a detailed explanation of the code:

• collapse Function Template:

  • The collapse function is a generic template function designed to work with both character and wide character strings (std::string and std::wstring).
  • It takes a single argument, str, which is a string of the corresponding character type.
  • The function's purpose is to remove consecutive duplicate characters from the input string.

• Implementation of collapse:

  • It uses the std::unique algorithm to find and eliminate consecutive duplicate characters in the input string.
  • std::unique takes an input iterator range and returns an iterator pointing to the end of the unique elements in that range.
  • The erase method is then used to remove the remaining duplicate characters from the end of the string.

• test Function:

  • The test function is used to demonstrate the functionality of the collapse function.
  • It takes a single argument, str, which is a constant string literal.
  • The function prints out the original string, its length, and the result of collapsing it using the collapse function.

• Main Function:

  • The main function is the entry point of the program.
  • It calls the test function with different string literals to demonstrate the collapse function's behavior on various input strings.

Example Outputs:

• Input String: ""

  • Collapsed String: ""

• Input String: ""If I were two-faced, would I be wearing this one?" --- Abraham Lincoln "

  • Collapsed String: ""If I wer faced, woud I be wear this on?" --- Abraham Lincoln "

• Input String: "..1111111111111111111111111111111111111111111111111111111111111117777888"

  • Collapsed String: ".1178"

• Input String: "I never give 'em hell, I just tell the truth, and they think it's hell. "

  • Collapsed String: "I never give 'em hell, I just tell the truth, and they think it's hell. " (No duplicates)

• Input String: " --- Harry S Truman "

  • Collapsed String: "--- Harry S Truman " (Removed extra spaces)

#include <string>
#include <iostream>
#include <algorithm>

template<typename char_type>
std::basic_string<char_type> collapse(std::basic_string<char_type> str) {
    auto i = std::unique(str.begin(), str.end());
    str.erase(i, str.end());
    return str;
}

void test(const std::string& str) {
    std::cout << "original string: <<<" << str << ">>>, length = " << str.length() << '\n';
    std::string collapsed(collapse(str));
    std::cout << "result string: <<<" << collapsed << ">>>, length = " << collapsed.length() << '\n';
    std::cout << '\n';
}

int main(int argc, char** argv) {
    test("");
    test("\"If I were two-faced, would I be wearing this one?\" --- Abraham Lincoln ");
    test("..1111111111111111111111111111111111111111111111111111111111111117777888");
    test("I never give 'em hell, I just tell the truth, and they think it's hell. ");
    test("                                                    --- Harry S Truman  ");
    return 0;
}