Redo <format> example

Author: mborland

examples/format.cpp

@@ -11,11 +11,30 @@
 
 int main()
 {
-    constexpr boost::decimal::decimal64_t val1 {314, -2};
-    constexpr boost::decimal::decimal32_t val2 {3141, -3};
-
+    constexpr boost::decimal::decimal64_t val1 {"3.14"};
+    constexpr boost::decimal::decimal32_t val2 {"3.141"};
+
+    // The easiest is no specification which is general format
+    // Given these values they will print in fixed format
+    std::cout << "Default Format:\n";
+    std::cout << std::format("{}", val1) << '\n';
+    std::cout << std::format("{}", val2) << "\n\n";
+
+    // Next we can add a type modifier to get scientific formatting
+    std::cout << "Scientific Format:\n";
+    std::cout << std::format("{:e}", val1) << '\n';
+    std::cout << std::format("{:e}", val2) << "\n\n";
+
+    // Next we can add a type modifier to get scientific formatting
+    // Here this gives one digit of precision rounded according to current rounding mode
+    std::cout << "Scientific Format with Specified Precision:\n";
+    std::cout << std::format("{:.1e}", val1) << '\n';
+    std::cout << std::format("{:.1e}", val2) << "\n\n";
+
+    // This combines the padding modifier (10), precision (3 digits), and a type modifier (e)
+    std::cout << "Scientific Format with Specified Precision and Padding:\n";
     std::cout << std::format("{:10.3e}", val1) << '\n';
-    std::cout << std::format("{:10.3e}", val2) << std::endl;
+    std::cout << std::format("{:10.3e}", val2) << '\n';
 
     return 0;
 }