C Language Basics _ Pointers

First, the pointer variable

1. Variables for storing addresses

2. * Indirect address character

3.%p The format character of the print address

4. & Take address character to get the storage unit address of the variable

5, int *p = &a p points to a storage unit [p is a variable where the pointer stores the address]

6. *p storage unit (content) for accessing variables via address

Second, the pointer

    int a[5]={3,4,1,2,5};       int *p = A; // define a pointer to the first address    printf ("p[2] =%d\n", p[1]);    printf ("%d\n", * (p+1));  

Three, a string pointer

    CharStr[] ="Hello"; Char* PS =str; intCount =0;//int n = 0;     for(inti =0; Str[i]! =' /'; i++) {//* (ps+n)! = ' + ';printf"%c", *ps);//n++;ps++; Count++; } printf ("%d", count);

Iv. exchange of two variables

voidSwapint*a,int*b) {    inttemp = *A; *a = *b; *b =temp; printf ("%d%d", *a,*b);} intMainintargcConst Char*argv[]) {    intA =1; intb =2; Swap (&a,&b);return 0;}

Five, array sorting

voidAddint*arr,intLen) {     for(inti =0; I < len-1; i++) {         for(intj =0; J < Len-1-I.; J + +) {            if(* (ARR+J) > * (arr+j+1)) {                inttemp = * (arr+j); * (ARR+J) = * (arr+j+1); * (arr+j+1) =temp; }        }    }     for(inti =0; i < Len; i++) {printf ("%d", * (arr+i)); }}intMainintargcConst Char*argv[]) {        intArr[] = { -, the, at, About,Panax Notoginseng}; Add (arr,5); return 0; }

1, array sort 2

voidAddint* p,intLen) {     for(inti =0; i<len-1; i++) {         for(intj =0; J < len-1-I.; J + +) {            if(* (P+J) >* (p+j+1)) {                inttemp; Temp= * (p+j); * (P+J) = * (p+j+1); * (p+j+1) =temp; }        }    }     for(inti =0; i < Len; i++) {printf ("%d", * (p+i)); }}intMainintargcConst Char*argv[]) {        intArr[] = { -, the, at, About,Panax Notoginseng}; int* p =arr;//defines the pointer to the first address of Add (p,5); return 0; }

C Language Basics _ Pointers