原课程链接：计算导论与C语言基础
Turing machine
The ranking is in descending order of price and working speed
- Register: carries operation data and results, as fast as a CPU
- Cache: data buffer
- Memory: the part that cannot be placed in the CPU
- External memory (hard disk, USB flash drive)
C. Bohm & G. Jacopini, “Flow Diagrams, Turing Machines and Languages with Only Two Formations Rules”, Communications of ACM, vol9(5) May 1966, pp 366-371.
Everything in the world is complicated, and there are only three kinds of logic expressed in programs:
- Sequence: the order of statements;
- Loop: for, while;
- Branch: if, else;
Knowledge structure of C-based languages:
More than 30 keywords
More than 10 basic data types;
More than 30 basic operation symbols;
3 basic logic statements;
1.5 Structured Programming Case
Data type change during the calculation.
char, short → int
int → unsigned → long → double
float → double
all will be changed to double if there is a double type data in the expression.
++i, before use i, must +1;
i++, after use i, must +1;
it could be used for variables but not expression such as below
errors: (-i)++, ++i++
-i, ++i, i++ all are an expressions, they could not be used for increment operation ++ or - - again.
more complicated increment operation
when debugging , you will find the order of operations on breakpoint step by step in specific compiler.
Logical NOT (!) > Arithmetic operation > Relational operation > “&&” and “｜｜” > Assignment operation
逻辑非(!) > 算术运算 > 关系运算 > “&&”和“｜｜” > 赋值运算
BITwise operators 按位运算符
C++ symbols
IO Manipulators