C语言温习

学习网站 http://www.cplusplus.com

#include <stdio.h>#include <stdlib.h>#include "hello.hpp"#include <string.h>#include <time.h>//c语言主要是面向过程，面向对象是一种思路，一种思维方式。void score(int score) {    if (score >= 90) {        printf("优秀\n");    }else if (score >= 80) {        printf("良好\n");    }else if (score >= 60) {        printf("及格\n");    }else{        printf("不及格\n");    }}void score1(int score) {    switch (score/10) {        case 9:            printf("优秀\n");            break;        case 8:            printf("良好\n");            break;        case 7:        case 6:            printf("及格\n");            break;        default:            printf("不及格\n");            break;    }}int Max(int a,int b) {    return a>b?a:b;}//C语言结构体struct People {    int age;    char *name;};//自定义类型，使用方便typedef struct{    int age;}People1;//定义函数指针,使用时直接用Func p;typedef void (*Func)();//函数void sayHello() {    printf("Hello C\n");}//面向对象思想//ObjectStart>>>>>>>>>>>>>>>>>>>>>#define ObjectField \    void(*onDelete)(void *);typedef struct Object {    ObjectField}Object;#define ObjectCreate(TYPE) malloc(sizeof(TYPE))#define ObjectDelete(obj) {\    obj->onDelete(obj);\    free(obj);\}void ObjectOnDelete(void *obj) {    printf("Object on delete\n");}Object *ObjectInit(Object *obj) {    obj->onDelete = ObjectOnDelete;    return obj;}//ObjectEnd<<<<<<<<<<<<<<<<<<<<<<<//People2Start>>>>>>>>>>>>>>>>>>>>>typedef struct{    ObjectField    int age;    void(*sayHello)();}People2;void peopleSayHello() {    printf("PeopleSayHello\n");}void peopleOnDelete(void *p) {    ObjectOnDelete(p);    printf("People2 On Delete\n");}People2 *peopleInit(People2 *p,int age) {    ObjectInit((Object *)p);        p->age = age;    p->sayHello = peopleSayHello;    p->onDelete = peopleOnDelete;    return p;}//People2End<<<<<<<<<<<<<<<<<<<<<<<int main(int argc, const char * argv[]) {    // insert code here...//    printf("Hello, World!\n");//    score(88);//    score1(59);//    //    printf("%d\n",Max(10, 20));    //    for (int i = 0; i < 100; printf("%d\n",i ++)) {//        printf(">>>\n");//    }    //    int i = 0;//    do {//        printf("%d\n",i);//        i ++;//    } while (i < 100);    /*    struct People p;    p.age = 10;    p.name = "XiaoYang";    printf("name=%s  age=%d\n",p.name,p.age);    //    结构体赋值为copy，两个指针不想相同    struct People p1 = p;    printf("name=%s  age=%d\n",p1.name,p1.age);        p.name = "YangXiao";    p.age = 11;    printf("修改p后p：name=%s  age=%d\n",p.name,p.age);    printf("修改p后p1：name=%s  age=%d\n",p1.name,p1.age);*/    /*//    malloc(<#size_t#>)函数需要导入#include <stdlib.h>库    struct People *p = malloc(sizeof(struct People));    p->age = 10;    p->name = "XiaoYang";//    结构体指针赋值的是retain，两个指针相同    struct People *p1 = p;    p->age = 11;    p->name = "YangXiao";    printf("修改p后p1：name=%s  age=%d\n",p1->name,p1->age);//     结构体指针在不用的时候需要释放，因为两个结构体的指针相同，所以只需要释放一次    free(p);        printf("p指针=%p  p1指针=%p\n",p,p1);*/        /*//    通常调用函数直接调用：sayHello();//    声明一个返回值为void的函数指针p,p只能赋值返回值为void类型的函数指针    void (*p)();    printf("赋值前%p\n",p);//    函数指针赋值为sayHello    p = sayHello;    printf("赋值后%p\n",p);//    执行函数指针    p(); */    //    People2 *p2 = peopleInit(ObjectCreate(People2), 10);//    printf("%d\n",p2->age);//    p2->sayHello();//    ObjectDelete(p2);    //    sayHello();    ////    定义一个缓冲区//    char buf[100];////    清空一片区域//    memset(buf, 0, 100);////    拼接一段字符串,需要导入文件<string.h>//    sprintf(buf, "Hello %d,%.2f,%s\n",100,1.2,"拼接完成");//    printf("%s",buf);    //    写入数据//    FILE *f = fopen("data.text", "w");//    if (f != NULL) {//        fprintf(f, "Hello c");//    }//    fclose(f);    ////    读取数据//    FILE *f = fopen("data.text", "r");////    读取到最后一个字节//    fseek(f, 0, SEEK_END);//    long size = ftell(f);//    char buf[size + 1];////    重置到第一个字节//    fseek(f, 0, SEEK_SET);////    把文件读取到buf里//    fread(buf, sizeof(unsigned char), size, f);////    设置\0结尾//    buf[size] = '\0';//    fclose(f);//    printf("%s\n",buf);    //    猜数字小游戏start>>>>>>>>>>>>>>>>>>>>>>>>>>>>//    需要导入<stdlib.h>//    rand()方法需要一个种子，根据种子来生成随机数，这里选用系统时间，需要导入time.h    srand((int)time(NULL));    int randNum = rand()%100;    printf("请输入一个0-100中间的数字\n");        int userInput;    while (1) {        scanf("%d",&userInput);                if (userInput > randNum) {            printf("输入值过大\n");        }else if (userInput < randNum) {            printf("输入值过小\n");        }else{            printf("正确\n");            break;        }    }        printf("exit\n");//    猜数字小游戏end<<<<<<<<<<<<<<<<<<<<<<<<<<<<        return 0;}