Remove pragma guards for C++17

This project already requires C++17, so these pragma guards are no
longer needed. This patch removes them from "strings_1_main.cpp".

CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.4.3 FATAL_ERROR)
+cmake_minimum_required(VERSION 3.20)
 
 project(cpp-tutor)
 

README.md

@@ -146,7 +146,7 @@ Set the `CMAKE_BUILD_TYPE` variable to:
     configured to be run with address sanitzer
 
 ### Switching between C++ standards
-The default C++ standard for the whole project is set to C++14. In order to
+The default C++ standard for the whole project is set to C++17. In order to
 rebuild using `C++11` or `C++17`, use `CMAKE_CXX_STANDARD`. For example, to
 build in `C++17` mode:
 ```bash

src/strings_1_main.cpp

@@ -20,9 +20,7 @@
 #include <algorithm>
 #include <iostream>
 #include <string>
-#if __cplusplus >= 201703L
 #include <string_view>
-#endif
 
 #include "../include/strings_reverse.hpp"
 
@@ -38,19 +36,15 @@ int main(int argc, const char** argv) {
   // trigger UB. Hence `const char*` is what makes most sense here.
   const char* hello_c_c = "Hello World!";
   std::string hello_cpp(hello_c);
-#if __cplusplus >= 201703L
   std::string_view hello_sv(hello_cpp);
-#endif
 
   //-------------------------------------------------------------------------
   // 2. PRINT THE STRINGS
   //-------------------------------------------------------------------------
   std::cout << "C-string (char[]): " << hello_c << std::endl;
   std::cout << "C-string (const char*): " << hello_c_c << std::endl;
   std::cout << "C++ string: " << hello_cpp << std::endl;
-#if __cplusplus >= 201703L
   std::cout << "C++ string_view: " << hello_sv << std::endl;
-#endif
   std::cout << std::endl;
 
   //-------------------------------------------------------------------------
@@ -59,9 +53,7 @@ int main(int argc, const char** argv) {
   std::cout << "Size of hello_c: " << sizeof(hello_c) << std::endl;
   std::cout << "Size of hello_c_c: " << sizeof(hello_c_c) << std::endl;
   std::cout << "Size of hello_cpp: " << sizeof(hello_cpp) << std::endl;
-#if __cplusplus >= 201703L
   std::cout << "Size of hello_sv: " << sizeof(hello_sv) << std::endl;
-#endif
   std::cout << std::endl;
 
   //-------------------------------------------------------------------------
@@ -82,14 +74,12 @@ int main(int argc, const char** argv) {
   reverse_cpp_str_alg(&hello_cpp);
   std::cout << "Reverse of hello_cpp: " << hello_cpp << std::endl;
 
-#if __cplusplus >= 201703L
 #ifdef COMPILATION_ERROR
   // string_view is non-modifiable!
   reverse_cpp_str_swap(&hello_sv);
   reverse_cpp_str_alg(&hello_sv);
   std::reverse(hello_sv.begin(), hello_sv.end());
   std::cout << "Reverse of hello_sv: " << hello_sv << std::endl;
-#endif
 #endif
 
   cppt::footer(argv[0]);