struct-Body pointer

Main function

Main.m

C9_ structure pointer

//

Created by Dllo on 15/7/10.

Copyright (c) 2015 CML. All rights reserved.

//

#import <Foundation/Foundation.h>

#import "MyFunction.h"

A macro is a replacement process that replaces the contents of the following

# define PI 3.14

Macros with parameters

Calculates the two-digit and

# define MUL (A) (A) (A) * (b)

Parentheses are needed to prevent this problem from being affected by the precedence of the arithmetic notation.

# define MAXVALUE (A, b) a>b? A:b

First conditional compilation

#ifdef PI

#define TEST 20

#else

#define TEST 50

#endif

Second conditional compilation

#ifndef PI

#define TEST 20

#else

#define TEST 50

#endif

Third Kind

There are two kinds of conditions, one is 0, the other is 1.

#if 0

int a = 10;

#define TEST 20

#else

int a = 50;

#define TEST 50

#endif

int main (int argc, const char * argv[]) {

printf ("%ld\n", sizeof (STU));

//

Define a variable of struct type

Stu Stu = {70.5, ' w ', ' Zhangsan '};

With. To access member variables

printf ("%s\n", stu.stuname);

//

Structs can be assigned directly

Stu temp = Stu;

Constant address (array cannot be assigned directly)

int arr[2]={1,2};

x int Arr1[2]=arr;

Pointer variable

int *p =null;

int a = 10;

Char str[20]= "";

scanf ("%s", str);

printf ("%p\n", &a);

P =&a;

* Value Symbol

printf ("%d\n", *p);

//

int arr[5] ={3,4,6,5,1};

int *p=arr;

Bubble (P, 5);

for (int i =0; i<5; i++) {

printf ("%d\n", Arr[i]);

//    }

Custom data types

Stu Stu ={20, 70.5, ' W ', ' Yanglin '};

Stu *p =&stu;

printf ("%p\n", p);

printf ("%p\n", &stu);

P holds the address of the struct, and the result of the *p is equivalent to the variable of the struct that corresponds to the address, and then the usage is the same as the struct

printf ("%s\n", (*p). Stuname);

strcpy ((*p). Stuname, "Liushasha");

printf ("%s\n", (*p). Stuname);

//    //

printf ("%p\n", &stu.stuage);

printf ("%p\n", &stu.stuscore);

printf ("%s\n", p->stuname);

//

////

Cpoint m={8,11};

Cpoint n={5,7};

Cpoint *p1=&m;

Cpoint *p2=&n;

Distance (P1,P2);

//

Student Stu ={1, "L an OU", ' m ', 95.6};

Student *p=&stu;

printf ("%c\n", p->name[0]);

//

Change (p);

struct array

Student stu1 = {20,75.5, ' w ', ' Zhangsan '};

Student STU2 = {30,80.5, ' m ', ' Lisi '};

Student Stu3 = {33,90.5, ' w ', ' Wangwu '};

Student Stu4 = {23,87, ' m ', ' Yanglin '};

Student Stu[4] = {STU1,STU2,STU3,STU4};

printf ("%p\n", Stu);

printf ("%p\n", stu[0]);

Student *p = stu;

Stu[i] and p[i] like, the structure is taken out, so use. To find member variables

(p+1) is a pointer-based operation that accesses member variables

printf ("%s\n", p->stuname);

printf ("%s\n", p[0]);

With pointers to the way to traverse, all student names

for (int i =0; i<4; i++) {

printf ("%s\n", (p+i)->stuname);

//    }

//

According to the student's grade, the order is only for him, from the big to the small

for (int i =0; i<3; i++) {

for (int j=0; j<3-i; J + +) {

if (P[i].stuscore<p[i+1].stuscore) {

Student temp;

//

TEMP=P[J];

P[J]=P[J+1];

P[j+1]=temp;

//            }

//        }

//    }

for (int i =0; i<4; i++) {

printf ("%g\n", P[i].stuscore);

//    }

Average score and average age

int agecount = 0;

float Scorecount = 0;

for (int i =0; i<4; i++) {

Agecount + = (p+i)->stuage;

Scorecount + = (p+i)->stuscore;

//    }

printf ("%d\n", AGECOUNT/4);

Structure Array Exercises

Grade (&STU);

Student *p =&stu;

//

for (int i =0; i<4; i++) {

printf ("%g\n", P[i].stuscore);

//    }

Person per1={"Yanglin", 111,123,100};

Person per2={"Lishanshan", 222,234,200};

Person per3={"Shangshuai", 333,345,300};

Person per4={"Wangwu", 444,456,400};

Person Per[4]={per1,per2,per3,per4};

Enter the account password, correctly return the subscript, incorrect return 4

while (1) {

int entercard = 0;

scanf ("%d", &entercard);

int enterpassword = 0;

scanf ("%d", Enterpassword);

Person *p=per;

int result =checkpasscardandpassword (Entercard, Enterpassword, p, 4);

if (result = = 4) {

printf ("Error \ n");

Continue;

}else {

printf ("Login successful \ n");

//    }

//    }

Macro definition

Define a macro, name either all uppercase, or K + hump the Way

printf ("%g\n", pi+30);

int a =10, b = 20;

printf ("%d\n", MAXVALUE (A, b));

printf ("%d\n", MUL (3+4, b));

printf ("%d\n", TEST);

printf ("test =%d\n", a);

return 0;

}

. h file

//

MyFunction.h

C9_ structure pointer

//

Created by Dllo on 15/7/10.

Copyright (c) 2015 CML. All rights reserved.

//

#import <Foundation/Foundation.h>

declaring struct bodies

Student: Name, age, gender, score, last use typedef

//

struct student{

int stuage;

float Stuscore;

Char Stusex;

Char stuname[20];//member variable

};

typedef struct student student;

struct student{

Long A;

char c;

//

Char D;

int b;

//};

typedef struct Student Stu;

Use a pointer to bubble sort

void Bubble (int *p,int count);

//

Prescribing

struct cpoint{

float x;

Float y;

//};

typedef struct CPOINT CPoint;

void distance (Cpoint *p1,cpoint *p2);

struct stu{

int num;

Char name[20];

char sex;

Float score;

//};

typedef struct STU Student;

void Change (Student *stu);

void Grade (Student *stu);

Name, account number, password, balance

struct person{

Char name[30];

int cardnum;

int PassWord;

int moneycount;

};

typedef struct person person;

int Checkpasscardandpassword (int entercard,int passWord, person *p,int count);

If the money is just taken away, the balance is zero, a "00" is appended to the name, and the amount of money taken away is modified and printed, and it needs to be judged not enough

int Checkmoney (int postion, person *p,int Getmoney);

. m file

/MYFUNCTION.M

C9_ structure pointer

//

Created by Dllo on 15/7/10.

Copyright (c) 2015 CML. All rights reserved.

//

#import "MyFunction.h"

Use a pointer to bubble sort

//

void Bubble (int *p,int count) {

for (int i =0; i<count-1; i++) {

for (int j=0; j<count-1-i; J + +) {

if (P[j]>p[j+1]) {//* (p+j) =p[j]

int temp =P[J];

P[J]=P[J+1];

P[j+1]=temp;

//            }

//        }

//    }

//}

//

void distance (Cpoint *p1,cpoint *p2) {

Fetch Address

float distance = 0;

//

Distance=sqrt (((p1->x)-(P2->X)) * ((p1->x)-(p2->x)) + ((p1->y)-(P2->y)) * ((P1->y)-(P2->y) ));

//

printf ("%g\n", distance);

//}

//

//

//

void Change (Student *stu) {

//

Determine if the first letter is lowercase

if (stu->name[0]>= ' a ' &&stu->name[0]<= ' Z ') {

Stu->name[0]-= (' A '-' a ');

//    }

for (int i =0; I<strlen (stu->name); i++) {

if (stu->name[i]== ') {

Stu->name[i]= ' _ ';

//        }

//    }

printf ("%s\n", stu->name);

//}

//

void Grade (Student *stu) {

//

for (int i =0; i<4; i++) {

if (stu[i].stusex== ' m ') {

Stu[i].stuscore +=10;

//        }

if (stu[i].stuscore>100) {

stu[i].stuscore=100;

//        }

//

//    }

//

//}

int Checkpasscardandpassword (int entercard,int passWord, person *p,int count) {

for (int i =0; i<count; i++) {

if ((Entercard = = P[i].cardnum) && (Password==p[i].password)) {

return i;

}

}

return 4;

}

int Checkmoney (int postion, person *p,int Getmoney) {

while (1) {

scanf ("%d", &getmoney);

if (Getmoney>p[postion].moneycount) {

printf ("The balance is insufficient, please re-enter \ n");

}else if (getmoney==p[postion].moneycount) {

The money's just gone.

strcat (P[postion].name, "00");

printf ("Balance:%d\n", P[postion].moneycount);

}else{

P[postion].moneycount-= Getmoney;

printf ("Balance:%d\n", P[postion].moneycount);

}

}

return 1;

}

struct-Body pointer