Currency conversions

3rd-party/ttmath-0.9.3/samples/big2.cpp

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+#include <ttmath/ttmath.h>
+#include <iostream>
+
+
+// this is a similar example to big.cpp
+// but now we're using TTMATH_BITS() macro
+// this macro returns how many words we need to store
+// the given number of bits
+
+// TTMATH_BITS(64) 
+//   on a 32bit platform the macro returns 2 (2*32=64)
+//   on a 64bit platform the macro returns 1
+
+// TTMATH_BITS(128)
+//   on a 32bit platform the macro returns 4 (4*32=128)
+//   on a 64bit platform the macro returns 2 (2*64=128)
+
+// Big<exponent, mantissa>
+typedef ttmath::Big<TTMATH_BITS(64), TTMATH_BITS(128)> MyBig;
+
+// consequently on a 32bit platform we define: Big<2, 4>
+// and on a 64bit platform: Big<1, 2>
+// and the calculations will be the same on both platforms       
+       
+       
+void SimpleCalculating(const MyBig & a, const MyBig & b)
+{
+	std::cout << "Simple calculating" << std::endl;
+	std::cout << "a = " << a << std::endl;
+	std::cout << "b = " << b << std::endl;
+	std::cout << "a + b = " << a+b << std::endl;
+	std::cout << "a - b = " << a-b << std::endl;
+	std::cout << "a * b = " << a*b << std::endl;
+	std::cout << "a / b = " << a/b << std::endl;
+}
+
+
+void CalculatingWithCarry(const MyBig & a, const MyBig & b)
+{
+MyBig atemp;
+
+	std::cout << "Calculating with a carry" << std::endl;
+	std::cout << "a = " << a << std::endl;
+	std::cout << "b = " << b << std::endl;
+
+	atemp = a;
+	if( !atemp.Add(b) )
+		std::cout << "a + b = " << atemp << std::endl;
+	else
+		std::cout << "a + b = (carry)" << std::endl;
+		// it have no sense to print 'atemp' (it's undefined)
+
+	atemp = a;
+	if( !atemp.Sub(b) )
+		std::cout << "a - b = " << atemp << std::endl;
+	else
+		std::cout << "a - b = (carry)" << std::endl;
+		
+	atemp = a;
+	if( !atemp.Mul(b) )
+		std::cout << "a * b = " << atemp << std::endl;
+	else
+		std::cout << "a * b = (carry)" << std::endl;
+		
+		
+	atemp = a;
+	if( !atemp.Div(b) )
+		std::cout << "a / b = " << atemp << std::endl;
+	else
+		std::cout << "a / b = (carry or division by zero) " << std::endl;
+	
+}
+
+
+int main()
+{
+MyBig a,b;
+	
+	// conversion from 'const char *'
+	a = "123456.543456";
+	b = "98767878.124322";
+	
+	SimpleCalculating(a,b);
+	
+	// 'a' will have the max value which can be held in this type
+	a.SetMax();
+	
+	// conversion from double
+	b = 456.32;
+	
+	// Look at the value 'a' and the product from a+b and a-b
+	// Don't worry this is the nature of floating point numbers
+	CalculatingWithCarry(a,b);
+}
+
+/*
+the result (the same on a 32 or 64bit platform):
+
+Simple calculating
+a = 123456.543456
+b = 98767878.124322
+a + b = 98891334.667778
+a - b = -98644421.580866
+a * b = 12193540837712.270763536832
+a / b = 0.0012499665458095764605964485261668609133
+Calculating with a carry
+a = 2.34953455457111777368832820909595050034e+2776511644261678604
+b = 456.3199999999999931787897367030382156
+a + b = 2.34953455457111777368832820909595050034e+2776511644261678604
+a - b = 2.34953455457111777368832820909595050034e+2776511644261678604
+a * b = (carry)
+a / b = 5.1488748127873374141170361292780486452e+2776511644261678601
+*/