Explicit keyword usage

Author: ramkumarrammohan

basics_using_cpp.pro

@@ -4,3 +4,6 @@ CONFIG -= app_bundle
 CONFIG -= qt
 
 DISTFILES += *.md
+
+SUBDIRS += \
+    keyword_explicit

keyword_explicit/README.md

@@ -0,0 +1,8 @@
+# keyword_explicit
+Understanding of ***explicit*** keyword behaviour in cpp prog.
+
+In general if a class has a constructor which can be called with a single argument, then this constructor becomes conversion constructor because such a constructor allows conversion of the single argument to the class being constructed.
+
+We can make the constructor explicit(doesn't allow implicit conversions) with the help of ***explicit*** keyword.
+
+To get clear understanding [click here!](https://stackoverflow.com/a/31351956/5903276).

keyword_explicit/keyword_explicit.pro

@@ -0,0 +1,9 @@
+TEMPLATE = app
+CONFIG += console c++11
+CONFIG -= app_bundle
+CONFIG -= qt
+
+SOURCES += main.cpp
+
+DISTFILES += *.md \
+    README.md

keyword_explicit/main.cpp

@@ -0,0 +1,52 @@
+#include <iostream>
+#include <string>
+
+using namespace std;
+
+class Price
+{
+public:
+    Price(double amount = 0.00) : m_amount(amount) {}
+
+    void print() {
+        cout << "My price: " << m_amount << endl;
+    }
+
+private:
+    double m_amount;
+};
+
+
+class PriceExplicit
+{
+public:
+    explicit PriceExplicit(double amount = 0.00) : m_amount(amount) {}
+
+    void print() {
+        cout << "My price: " << m_amount << endl;
+    }
+
+private:
+    double m_amount;
+};
+
+
+int main()
+{
+    cout << "!!! Keyword explicit !!!\n" << endl;
+
+
+    // No need to typecast
+    Price pr = 8.00;
+    pr.print();
+
+
+    // Typecast must needed here or else it ill throw compilation err as below
+    // "error: conversion from ‘double’ to non-scalar type ‘PriceExplicit’ requested"
+    // Uncomment below line and expect same error stated above
+    //    PriceExplicit prExp = 8.00;
+    PriceExplicit prExp = (PriceExplicit)8.00;
+    prExp.print();
+
+    return 0;
+}