<ratio>

The <ratio> header file declares the ratio class template and auxilary types to operate with them. Simply stating, the <ratio> header file helps to deal with ratios. A ratio can be defined as follows.

typedef ratio<numerator, denominator> sample;

where 'numerator' and 'denominator' are numerator and denominator of the ratio 'sample' respectively. And, they can be accessed as sample::num and sample::den respectively.

This code can be used to perform arithmetic on two ratios.


	            typedef ratio<1, 2> r1;

                typedef ratio<3, 4> r2;


                typedef ratio_add<r1, r2> radd;

                cout << "Add : " << radd::num << "/" << radd::den << endl;


                typedef ratio_subtract<r1, r2> rsub;

                cout << "Sub : " << rsub::num << "/" << rsub::den << endl;


                typedef ratio_multiply<r1, r2> rmul;

                cout << "Mul : " << rmul::num << "/" << rmul::den << endl;


                typedef ratio_divide<r1, r2> rdiv;

                cout << "Div : " << rdiv::num << "/" << rdiv::den << endl;

It outputs the addition, subtraction, multiplication and division of the two ratios 1:2 and 3:4 (Try It Yourself!).

The auxilary types used in the above code i.e. ratio_add, ratio_subtract, ratio_multiply and ratio_divide are illustrated in the next lesson.

Fill in the Blanks to output the numerator of a ratio named "rSample"

cout << << endl;

Ratio Operations

Here is the list of operations that can be made on ratios using <ratio>.

Operation	Description
Arithmetic Operators
ratio_add<r1, r2>	Addition of r1 and r2
ratio_subtract<r1, r2>	Subtraction of r1 and r2
ratio_multiply<r1, r2>	Multiplication of r1 and r2
ratio_divide<r1, r2>	Division of r1 and r2
Comparison Operators
ratio_less<r1, r2>	Equal to 1 if r1 is less than r2
ratio_greater<r1, r2>	Equal to 1 if r1 is greater than r2
ratio_equal<r1, r2>	Equal to 1 if r1 is equal to r2
ratio_less_equal<r1, r2>	Equal to 1 if r1 is less than or equal to r2
ratio_greater_equal<r1, r2>	Equal to 1 if r1 is greater than or equal to r2
ratio_not_equal<r1, r2>	Equal to 1 if r1 is not equal to r2

Here, r1 and r2 are two ratios. Using the <ratio> header file, ratios can be compared (Try It Yourself!).

Fill in the Blanks to output 1 if ratio r1 is not equal to ratio r2.

cout << <r1, r2>::value << endl;

<ratio> - C++ header