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// Playing with bool, true, and false.
#include <iostream>
using namespace std;

// user defined function
bool func()
{
   // Function returns a bool type
   return NULL;
   // NULL is converted to Boolean false, same
   // as statement 'return false;'
}

int main()
{
   bool val = false;  // Boolean variable
   int i = 1;         // i is neither Boolean-true nor Boolean-false
   int g = 5;
   float j = 3.02;    // j is neither Boolean-true nor Boolean-false

   cout<<"Given the test value: "<<endl;
   cout<<"\nbool val = false "<<endl;
   cout<<"int i = 1 "<<endl;
   cout<<"int g = 5 "<<endl;
   cout<<"float j = 3.02 "<<endl;
   cout<<"\nTESTING\n";

   // Tests on integers
   if(i == true)
      cout<<"True: value i is 1"<<endl;
   if(i == false)
      cout<<"False: value i is 0"<<endl;
   if(g)
      cout << "g is true."<<endl;
   else
      cout << "g is false."<<endl;

   // To test j's truth value, cast it to bool type.
   if(bool(j) == true)
      cout<<"Boolean j is true."<<endl;

   // Test Boolean function returns value
   val = func();

   if(val == false)
      cout<<"func() returned false."<<endl;

   if(val == true)
      cout<<"func() returned true."<<endl;
   
   // false is converted to 0
   return false;
}