Pointer
1. Overview of pointers
What is the pointer?
Pointer is an address is a constant
Int int a a is a variable
What does the pointer do?
Easy to use arrays or strings to process memory addresses like assembly language
2. Pointer variable
What is a pointer variable?
Is a "container" that can store addresses
Often, the pointer variable is read after the pointer, the address is used as the pointer, and the variable storing the address is called the pointer variable
3. Pointer assignment
Type specifier * variable name = address value;
int a=89;
Int * P = & A; defines a variable p of type int * (type and * are good friends)
Then assign the address of a to this variable & take the address symbol
1 #include<stdio.h> 2 int main() 3 { 4 //int a = 520; 5 //int *p = &a; 6 //printf("p=%d\n",p); 7 //printf("a Address=%d\n",&a); 8 9 //int a = 520; 10 //int *p = &a;//First, initialize when defining pointer variables 11 //int *pp; 12 //pp = &a;//Second, assign the address value of a variable to a pointer variable of the same type 13 ////Be similar to 14 //int c; 15 //c = 5; 16 //int *ppp = pp;//Assign a pointer variable to another pointer variable with the same data 17 //printf("ppp=%d\n",ppp); 18 //printf("pp=%d\n", pp); 19 //printf("pp=%d\n", &a); 20 21 //int a = 5; 22 //char xiaoming = 'A'; 23 //int *PangQi = &a; 24 //PangQi = (int*)&xiaoming;//Pointer assignment can only be of the same type. If you have to assign addresses of different types, you need to force the type conversion 25 //printf("%d\n",*PangQi); 26 27 //int a = 4407873;//int Is 4 bytes 32 bits 28 //char *p = (char *)&a;//char Is 1 byte 8 bits 29 //printf("%s\n",p);//output ABC 30 ////ABCD 0100 0100 0100 0011 0100 0010 0100 0001 31 32 //Quoting c There are two operators about pointer in language * & 33 /* 34 & Take the address sign int a & A to get the address of a 35 * Pointer operator or join operator between pointer operators 36 "*"Its function is to refer to the variable value pointed to by the pointer. The reference is actually the address of the variable 37 "To solve "is to find out what the address corresponds to 38 */ 39 int xiaoming = 10000; 40 int *pangqi = &xiaoming; 41 *pangqi = 10000-8880; 42 printf("%d\n",*pangqi); 43 44 45 46 getchar(); 47 return 0; 48 }
2018-07-24 16:32:13