这是《C／C++程序员实用大全》上面的源码

				#include 
				
				bool func(void)
				 {    				// Function returns a bool type
				   return false;
				   //  return NULL;  // NULL is converted to Boolean false
				 }
				
				void main(void) 
				{
				   bool val = false;  // Boolean variable
				   int i = 1;         // i is neither Boolean-true nor Boolean-false
				   int g = 3;
				   int *iptr = 0;     // null pointer
				   float j = 1.01;    // j is neither Boolean-true nor Boolean-false
				
				   if (i == true)
				      cout 				   if (i == false)
				      cout 				   if (g)
				      cout 				   else
				      cout 				
				   // Test on pointer
				   if (*iptr == false)
				      cout 				   if (*iptr == true)
				      cout 				
				   // To test j's truth value, cast it to bool type.
				   if (bool(j) == true)
				      cout 				
				   // Test Boolean function return value
				
				   val = func();
				   if (val == false)
				      cout 				   if (val == true)
				      cout 				}