From 8d496a41c0a854fcd23b125f67161f9278ccef8e Mon Sep 17 00:00:00 2001
From: Suter Andreas <andreas.suter@psi.ch>
Date: Tue, 8 Sep 2015 08:50:26 +0200
Subject: [PATCH] added little root macro to check the c++ io formatting.

---
 src/tests/iotests/iotests.C | 99 +++++++++++++++++++++++++++++++++++++
 1 file changed, 99 insertions(+)
 create mode 100644 src/tests/iotests/iotests.C

diff --git a/src/tests/iotests/iotests.C b/src/tests/iotests/iotests.C
new file mode 100644
index 00000000..edaeda91
--- /dev/null
+++ b/src/tests/iotests/iotests.C
@@ -0,0 +1,99 @@
+// in order to illustrate the c++ io stream formatting
+// usage: 1) start root
+//        2) root 5.34.x -> .L iotests.C // root 6.x.y -> .L iotests.C+
+//        3) iotests()
+
+#include <iostream>
+using namespace std;
+
+void dump_ioflags(const ios_base::fmtflags flags)
+{
+  cout << endl << ">> flags decoded:" << endl;
+  if (flags & ios_base::boolalpha)
+    cout << ">> read/write bool elements as alphabetic strings (true and false)." << endl;
+  if (flags & ios_base::showbase)
+    cout << ">> write integral values preceded by their corresponding numeric base prefix." << endl;
+  if (flags & ios_base::showpoint)
+    cout << ">> write floating-point values including always the decimal point." << endl;
+  if (flags & ios_base::showpos)
+    cout << ">> write non-negative numerical values preceded by a plus sign (+)." << endl;
+  if (flags & ios_base::skipws)
+    cout << ">> skip leading whitespaces on certain input operations." << endl;
+  if (flags & ios_base::unitbuf)
+    cout << ">> flush output after each inserting operation." << endl;
+  if (flags & ios_base::uppercase)
+    cout << ">> write uppercase letters replacing lowercase letters in certain insertion operations." << endl;
+  if (flags & ios_base::dec)
+    cout << ">> read/write integral values using decimal base format." << endl;
+  if (flags & ios_base::hex)
+    cout << ">> read/write integral values using hexadecimal base format." << endl;
+  if (flags & ios_base::oct)
+    cout << ">> read/write integral values using octal base format." << endl;
+  if (flags & ios_base::fixed)
+    cout << ">> write floating point values in fixed-point notation." << endl;
+  if (flags & ios_base::scientific)
+    cout << ">> write floating-point values in scientific notation." << endl;
+  if (flags & ios_base::internal)
+    cout << ">> the output is padded to the field width by inserting fill characters at a specified internal point." << endl;
+  if (flags & ios_base::left)
+    cout << ">> the output is padded to the field width appending fill characters at the end." << endl;
+  if (flags & ios_base::right)
+    cout << ">> the output is padded to the field width by inserting fill characters at the beginning." << endl;
+  cout << "---" << endl;
+}
+
+void iotests()
+{
+  Double_t dval = 13.24;
+  
+  // default settings printout
+  cout << "default flags = " << cout.flags() << ":" << endl;
+  dump_ioflags(cout.flags());
+  cout << "dval = " << dval << endl;
+  cout << "++++" << endl << endl;
+  // printout of the 'floatfield' flags
+  cout << "ios_base::floatfield :" << ios_base::floatfield << endl;
+  dump_ioflags(ios_base::floatfield);
+  cout << "set floatfield flags." << endl;
+  cout.setf(ios_base::floatfield);
+  cout << "dval = " << dval << endl;
+  cout << "++++" << endl << endl;
+  // unset 'floatfield' flags in order to see if the default is recovered
+  cout.unsetf(ios::floatfield);
+  cout << "cout.unsetf(ios::floatfield) -> cout.flags()=" << cout.flags() << endl;
+  dump_ioflags(cout.flags());
+  cout << "dval = " << dval << endl;
+  cout << "++++" << endl << endl;
+  // set 'fixed' flag
+  cout.setf(ios_base::fixed);
+  cout << "cout.setf(ios_base::fixed) -> cout.flags()=" << cout.flags() << endl;
+  dump_ioflags(cout.flags());
+  cout << "dval = " << dval << endl;
+  cout << "++++" << endl << endl;
+  // unset 'fixed' flag and set 'scientific' instead
+  cout.unsetf(ios_base::fixed);
+  cout << "cout.unsetf(ios_base::fixed)" << endl;
+  cout.setf(ios_base::scientific);
+  cout << "cout.setf(ios_base::scientific) -> cout.flags()=" << cout.flags() << endl;
+  dump_ioflags(cout.flags());
+  cout << "dval = " << dval << endl;
+  cout << "++++" << endl << endl;
+
+  // precision playground according to http://www.cplusplus.com/reference/ios/ios_base/precision/
+  cout << "precision playground according to http://www.cplusplus.com/reference/ios/ios_base/precision/" << endl;
+  Double_t f = 3.14159;
+  cout.unsetf ( ios::floatfield );                // floatfield not set
+  cout << "cout.unsetf ( ios::floatfield ) -> cout.flags()=" << cout.flags() << endl; 
+  dump_ioflags(cout.flags());
+  cout.precision(5);
+  cout << "set cout.precision(5)" << endl;
+  cout << f << endl;
+  cout.precision(10);
+  cout << "set cout.precision(10)" << endl;
+  cout << f << endl;
+  cout.setf( ios::fixed,  ios::floatfield ); // floatfield set to fixed
+  cout << "cout.setf( ios::fixed,  ios::floatfield ) -> cout.flags()=" << cout.flags() << endl; 
+  dump_ioflags(cout.flags());
+  cout << f << endl;
+  cout << "++++" << endl << endl;
+}