Deep learning C++.2016_3_8

Another day, today Harvest very little, read the const qualifier, found that read not move, record, wash and sleep.

13. In a computer, the smallest addressable memory block is called a byte, and the information is stored and interpreted in bytes, 1 bytes (byte) = 8 bits (bit).

14, the word is the computer carries on the data processing, the first time accesses, the processing and transmits the information. The word length determines the actual number of bits to be processed at a time, and the longer the word length, the better the performance of the computer.

15. The C + + standard specifies the minimum value for the size of the arithmetic type, and colleagues allow the compiler to give these types a larger size.

16. A char is the same size as a machine byte.

17. The data type determines the number of bits that the data occupies and how the content of these bits is interpreted.

18, type char and signed char are not the same, the specific char type will behave as signed or unsigned depending on the compiler.

19, when the data outside the int range, you should choose long long, when performing floating-point operation as far as possible to choose the double type, because double and float type of calculation is similar to the cost, and float is less than double precision.

20, assigned to an unsigned number type a value that exceeds the range it represents, the result is that the initial value of the unsigned type represents the remainder of the total number of values modulo. If the unsigned int i =-1; in fact, it is assigned a value of 255. When a value that is assigned to a signed number type that exceeds the range it can represent, the result is undefined, which causes the program to place an error.

21. When there are both signed and unsigned types in the expression, the signed type is converted to an unsigned type.

22. The compiler adds a null character at the end of each string.

23, in C + +, initialization and assignment are two completely different operations, the meaning of initialization is to create a variable with an initial value, and the meaning of the assignment is to erase the current value by a new value override.

24, the built-in type in the use of the list initialization, if there is a risk of loss of information, will be error.

25. If you do not specify an initial value when defining a variable, a variable defined outside any function is initialized to 0 by default, and the built-in type variable defined inside the function body will not be initialized, and an error will occur when attempting to copy or access.

26. The declaration makes the variable name known to the program, and the definition is responsible for creating the entity associated with the name.

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Deep learning C++.2016_3_8