Knowledge Interest-c++,
Memory stack area: store the names of local variables.
Memory heap area: store objects from new or malloc.
Constant area: store the values of local variables or global variables.
Static area: store static variables and global variables.
Code area: store binary codes.
//main.cpp
int a = 0; 全局初始化区
char *p1; 全局未初始化区
main()
{
int b;// 栈
char s[] = "abc"; //"abc"在常量区，s在栈上。
char *p2; //栈
char *p3 = "123456"; //123456\0";在常量区，p3在栈上。
static int c =0； //全局（静态）初始化区
p1 = (char *)malloc(10);
p2 = (char *)malloc(20);
//分配得来得10和20字节的区域就在堆区。
strcpy(p1, "123456"); //123456\0放在常量区，编译器可能会将它与p3所指向的"123456"优化成一个地方。
}
Constructor: is a method of initializing an object when it is created.
Friendship function: A function defined outside the class, but has access to all private and protected members of the inner class; friendship destroys the encapsulation.
Member functions: ordinary functions in the class.
Polymorphism: It is not clear at compile time, and the method is determined when the program is running.
Pointer: Point to memory address; Pointer is a variable and can be changed; There is a null pointer.
Reference: the alias of the variable; it must be initialized before use, and cannot be changed after initialization; there is no reference to a null value.
TCP measures to ensure reliable transmission:
provide timeout retransmission,
discard duplicate data,
verify data,
flow control
Traversal of a two-dimensional list in python:
list2d = [[1,2,3],[4,5,6]]
sum = 0
for i in range(len(list2d)):
for j in range(len(list2d[0])):
sum += list2d[i][j]
print(sum)
How to determine whether a list contains an element in Python
if a[i] in a:
Deadlock: Several processes wait endlessly for other processes to release the resources they have occupied.
The three elements of
recursion : the purpose of
recursion, the termination condition of recursion,
find the equivalence relation of the function, that is, the recursion relation