C + + basic syntax

Document: Http://www.cprogramming.com/tutorial/lesson6.html

1. header file # include <string.h> is C language, and C + + is used with # include <string>

Otherwise, the following program cannot output a string:

int main () {

String a = "333ddd";

cout << a << Endl;

Cin.get ();

}

2.switch Case Statement

Note: The case cannot be a string and can only be of type int

int main ()
{
int a = 20;
Switch (a)
{
Case (10):
cout << "im ten" << endl;
Case (20):
cout << "im" << endl;
Default
cout << "im default" << Endl;
Break
}
Cin.get ();
return 0;
}

3. Hands, pointer

I can't read it. Document: http://www.cprogramming.com/tutorial/lesson6.html

Concept:

Pointer, also a variable. Its value holds the memory address of the other variable.

Eg: there are two ways to access variable A, one is to access cout << a directly,

The other is indirect access (that is, access with the address of a),

int A; Define int type variable A

int *p; Defines a pointer to the int type (int denotes the base type, * indicates that the variable p is a pointer type), and why the base type is defined, as described below.

p = &A; Pass the address of A to P (that is, the value of the variable p holds the address of a)

cout << p; Address of output A

cout << *p; Output variable a!!!!

Defined:

One pointer, one regular intint *pointer1, nonpointer1;//-Pointersint *pointer1, *pointer2;

Use:

#include <iostream>using namespace Std;int main () {   int x;            A Normal integer  int *p;           A pointer to an integer  p = &x;           Read it, "Assign the address of X to P"  cin>> x;          Put a value in X, we could also use *p here  cin.ignore ();  cout<< *p << "\ n"; Note the use of the * to get the value  cin.get ();}

Base type:

eg

int *p;

float *p;

String *p;

where int float string is the base type, since there is * to indicate that p is a pointer variable, why base type?

The reason for this is that there is p+1, which means that the value of P is +1, which is address +1, and that different int float string 1 is different, such as int is 2 bytes, string 4 bytes

4. Structural body

Concept:

A bit like a class, when used, you also have to instantiate an object.

Defined:

struct aaa{

int a = 10; The struct can only be initialized for shaping

String B;

}

Use:

AAA obj;

OBJ.B = "Im a string from struct";
cout << obj.a << obj.b <<endl;

Use pointers in structs:

struct aaa{

int a = 10;

}

AAA obj;

AAA *pointer;

pointer = &obj;

cout << pointer->a << Endl; Use, just like the object of a class invokes a method

5. Arrays

Defined:

String box[10]; Type and length must be specified

Use: (slightly)

Use pointers in arrays:

String box[10];

String *pointer;

pointer = &box;

6. Methods

Defined:

C + + basic syntax