C Axioms

My note for c++

1.1.1

Data type char16_t, char32_t, or wchar_t with variables assigned to an octal representation of unicode characters are converted to a decimal when used with std::cout while char in Octal representation is converted to a string literal.

Example

#include <iostream>int main(){    // The following are Octal representation of     // a unicode character M.    char16_t d1 = '\115';    char32_t d2 = '\115';    wchar_t d3 = '\115';    char d4 = '\115'    std::cout << d1 << " is the \x4d greatest number of all" << std::endl;    // d1, d2, d3 are converted to decimal, hence shows 77     // in the output but d4 will be converted to character M.     return 0;}

1.1.2

Hexadecimal (hex for short) representation uses A, B, C, D, E, F to represent numbers after 9. For example, 4D in hex is equivalent to 77 in decimal because D is equal to 13 and 4 * 16 + 13 = 77.

Example

#include <iostream>int main(){    char16_t yo = '\x4d';     // char16_t type converts to hex int with std::cout per 1.1.1    std::cout << yo << " is the greatest number of all " << std::endl;    // 77 is the greatest number of all    return 0;}

Note: Had A B C D E F not been used, it would have been more difficult to represent decimal numbers like 77 because \x4(13) is longer in length, and without the brackets, it will convert to a much bigger number.