ios指標第二天

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////  main.m//  LessonPointerPro////  Copyright (c) 2015年 池海濤. All rights reserved.//#import <Foundation/Foundation.h>#import "Function.h"#define PI 3.1415926#define kMul(A,B) (A)*(B)////條件編譯////形式1//#ifdef PI//#define kPPPI 0//#else//#define kPPPPI 1//#endif//////形式2//#ifndef kP////#define kP 3////#else////#define kP 4////#endif//////形式3//#if 0////#define kRong 0////#else////#define kRight 1////#endif//先行編譯指令//以#開頭的叫先行編譯指令:先行編譯時期做一些文本及代碼的替換工作//PI 代表宏名,3.14是先行編譯時期會被替換的內容int main(int argc, const char * argv[]) {//    //指標,指標變數//    int a = 10;//    int b = 6;//    change(&a,&b);//    //指標與函數//    //練習:交換兩個數的值//    printf("a = %d,b = %d",a,b);    /**     *            int a[5] = {0};     int count = sizeof(a) / sizeof(a[0]);          getArray(a,count);     */   // char strArray[4][20] = {"iPhone", "iPad", "ipod", "iWatch"};        //指標數組    /**     *  字串     char *strPinter[4] = {"iPhone", "iPad", "ipod", "iWatch"};     printStr(strPinter,4);     sortStrArray(strPinter,4);     printStr(strPinter,4);     */        //指標資料類型:Student *    //指標變數 :P    //初值:&student,儲存的是student的地址    //指標變數 p 所佔的位元組: 8個位元組////    Student student = {"chihaitao",‘m‘,23,100};//    //    Student *p = &student;        //通過指標訪問結構體成員    /**     *  *p 相當於student結構體變數     *///    printf("%s \n",student.name);// //    printf("%s \n",(*p).name);        /**     *  方式2     CPoint c1 = {4,5};     CPoint c2 = {7,1};          CPoint *p1 = &c1;     CPoint *p2 = &c2;          printf("%f    ", qiujuli(p1,p2));     // printf("%s \n",p->name);//通過指標,直接進行訪問, ->指向操作符     //使用->輸出結構體變數student中的所有成員變數     */    /**     *  <#Description#>     Student student = {"chihaitao",‘m‘,23,100};     Student stuArray[5] = {     {"chichi",‘m‘,25,99},     {"haihai",‘w‘,22,98},     {"taotao",‘w‘,23,97},     {"niuniu",‘w‘,22,98},     {"bibi",‘w‘,23,97},     };     //->就是指標操作    (指標)->(結構體成員)     Student *stu = stuArray;     //字串不能直接賦值,字串指標能賦值     (stu+4)->name = "fengfeng";     (stu+1)->age = 120;     printf("%s",(stu + 4)->name);     printf("%d",(stu+1)->age);     printf("%d",stuArray[4].age);     //printf("%s",m1->name);     printf("%f",stu[4].score);     printf("%p",(stu + 4));     printf("%p",&stuArray[4]);     //按學生年齡升序排列     for (int i = 0; i < 5 -1; i++) {     for (int j = 0;j < 5 - 1 - i; j++) {     if ((stu + j)->age > (stu+j + 1)->age) {     Student temp = *(stu + j);     *(stu + j) = *(stu + j + 1);     *(stu + j + 1)=temp;     }     }     }               */            //定義宏    //普通宏    //PI 代表宏名        int mul = kMul(3 + 1, 5);    printf("mul = %d\n",mul);    /**     * 宏與函數的區別     1.宏是在先行編譯時期進行替換的內容,不進行任何的邏輯檢測,只是簡單的賦值而已,運行速度比函數快     2.宏定義十不考慮參數的類型     3.參數宏在定義時記得多加括弧     4.參數宏在使用時會再目標檔案中村在多個副本,會增加目標檔案的大小          */#ifdef PI   //如果定義了 PI    printf("PI已經定義過了\n");#else    printf("PI沒有定義\n");#endif#ifndef PI  //如果沒有定義 PI    printf("PI這個宏沒有定義\n");#else    printf("早就定義過了\n");#endif    #if 1  //和條件判斷if else 用法一樣    printf("優衣庫被查了");#else    printf("你說啥 聽不懂\n");#endif            return 0;}

//--------Function.h

////  Function.h//  LessonPointerPro////  Created by laouhn on 15/7/27.//  Copyright (c) 2015年 池海濤. All rights reserved.//#import <Foundation/Foundation.h>struct student{    char *name;    char sex;    int age;    float score;};typedef struct student Student;typedef struct{    char *name;    char sex;    int age;    float score;} Student1;struct cpoint{    float x;    float y;};typedef struct cpoint CPoint;void change(int *,int *);void getArray(int *,int);void print(int *,int);void sortArray(int *,int);void printStr(char *[],int);void sortStrArray(char *[],int);float qiujuli(CPoint *,CPoint *);

//Function.m

////  Function.m//  LessonPointerPro////  Created by laouhn on 15/7/27.//  Copyright (c) 2015年 池海濤. All rights reserved.//#import "Function.h"void change(int *a,int *b){    int temp = *a;     *a = *b;    *b = temp;}void getArray(int *p,int count){        for (int i = 0; i < count; i++) {        *(p + i) = arc4random() % (100 - 10 + 1) + 10;    }    print(p,count);    sortArray(p, count);    print(p, count);}void print(int *a,int count){    for (int i = 0; i < count; i++) {        printf("%d ",*(a+i));    }    printf("\n");}void sortArray(int *a,int count){    for (int i = 0; i < count - 1; i++) {        for (int j = 0; j < count - i -1; j++) {            if (*(a + j) > *(a + j + 1)) {                int temp = *(a + j);                *(a + j) = *(a + j +1);                *(a + j + 1) = temp;            }        }    }}void printStr(char *b[],int count){    for (int i = 0; i < count; i++) {        printf("%s ",*(b + i));    }}void sortStrArray(char *str[],int count){    for (int i = 0; i < count - 1; i++) {        for (int j = 0; j < count - 1 - i; j++) {            if (strcmp(str[j],str[j + 1] ) > 0) {                char *temp = str[j];                str[j] = str[j + 1];                str[j + 1] = temp;            }        }    }}float qiujuli(CPoint *a,CPoint *b){    float x = fabsf(a->x - b->x);    float y = fabsf(a->y - b->y);    return sqrtf(x*x + y*y);}

 

ios指標第二天