c++14 integer maximum/small value

Table of Contents

• 1. How to get the maximum value
  • 1.1. Methods of C++14
  • 1.2. How to achieve maximum value by yourself
  • 1.3. How to implement the minimum value yourself

1 How to get the maximum value1.1 Methods of C++14

Std::cout << "int\t"  << std::numeric_limits<int>::lowest () << ' \ t '  << std:: Numeric_limits<int>::max () << ' \ n ';

The output is:

int-21474836482147483647

1.2 How to implement the maximum value yourself

int max_int = (int) ((unsigned) ~0 >> 1) cout << max_int << Endl;

The output is:

2147483647

The result is the same. This line of code needs to be interpreted:

• ~0 is reversed, all bits are set to 1
• (unsigned) transformation is to interpret the first position from the left as an unsigned bit, to prepare for the next right move
• >> 1 is shifted right one (divided by 2) because it is an integer of type unsigned, so the left side is 0
• The result is then converted to the target type int, because there is no overflow, so you can definitely

1.3 How to implement the minimum value yourself

int min =-(int) ((unsigned) ~0 >> 1)-1;

Just add the symbol based on the maximum value that has been calculated, and subtract one.

Author:dean

CREATED:2016-01-14 Four 10:37

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c++14 integer maximum/small value