1 files changed, 22 insertions, 0 deletions
diff --git a/challenge-287/ulrich-rieke/cpp/ch-2.cpp b/challenge-287/ulrich-rieke/cpp/ch-2.cpp
new file mode 100755
index 0000000000..b5dc14d07a
--- /dev/null
+++ b/challenge-287/ulrich-rieke/cpp/ch-2.cpp
@@ -0,0 +1,22 @@
+#include <iostream>
+#include <string>
+#include <regex>
+
+int main( ) {
+   std::cout << "Enter a string!\n" ;
+   std::string word ;
+   std::cin >> word ;
+   std::string inte {R"(^[-+]?\d+([eE]?[-+]?\d+)*$)"} ;
+   std::string decifirst {R"(^[-+]?\d+\.([eE]?[-+]?\d+)*$|^[-+]?\d+\.\d+([eE]?[+-]?\d+)*$)"} ;
+   std::string decisecond {R"(^[+-]?\.\d+([eE]?[+-]?\d+$)*$)" } ;
+   std::regex integer( inte ) ;
+   std::regex decimalfirst ( decifirst ) ;
+   std::regex decimalsecond ( decisecond ) ;
+   if ( std::regex_match( word , integer ) || std::regex_match( word , decimalfirst ) ||
+      std::regex_match( word , decimalsecond ) )
+      std::cout << "true" ;
+   else 
+      std::cout << "false" ;
+   std::cout << '\n' ;
+   return 0 ;
+}