Setting an int to Infinity in C++

I have an int a that needs to be equal to "infinity". This means that if

int b = anyValue;

a>b is always true.

Is there any feature of C++ that could make this possible?

Solution 1:

Integers are inherently finite. The closest you can get is by setting a to int's maximum value:

#include <limits>

// ...

int a = std::numeric_limits<int>::max();

Which would be 2^31 - 1 (or 2 147 483 647) if int is 32 bits wide on your implementation.

If you really need infinity, use a floating point number type, like float or double. You can then get infinity with:

double a = std::numeric_limits<double>::infinity();

Solution 2:

Integers are finite, so sadly you can't have set it to a true infinity. However you can set it to the max value of an int, this would mean that it would be greater or equal to any other int, ie:

a>=b

is always true.

You would do this by

#include <limits>

//your code here

int a = std::numeric_limits<int>::max();

//go off and lead a happy and productive life

This will normally be equal to 2,147,483,647

If you really need a true "infinite" value, you would have to use a double or a float. Then you can simply do this

float a = std::numeric_limits<float>::infinity();

Additional explanations of numeric limits can be found here

Happy Coding!

Note: As WTP mentioned, if it is absolutely necessary to have an int that is "infinite" you would have to write a wrapper class for an int and overload the comparison operators, though this is probably not necessary for most projects.