目录

1 本课概要... 1

2 C语言入口方法... 1

3 C语言标准输入与输出... 1

4 C语言方法调用... 2

5 C语言宏定义 – 在编译阶段... 2

6 C语言宏方法定义 – 在编译阶段，无类型... 3

7 C语言条件判断... 3

8 C语言循环... 4

9 C语言结构体 – 存储数据的集合 – 结构体的赋值，直接是内存的拷贝... 5

10 C语言结构体指针 - 同一块内存... 5

11 C语言函数指针... 6

12 C语言typedef关键字... 6

13 C语言面向对象 – 思维方式... 7

14 C语言引入自定义头文件... 9

15 C语言字符串操作 - sprintf 10

16 C语言文件操作 – fprintf、 fread. 10

17 C语言实现猜数字小游戏... 11

1 本课概要

2 C语言入口方法

#include <stdio.h>

int main(int argc, const char * argv[]) {  //argc从控制台传进来参数的数量，argv[]从控制台传入参数的值
int i;
for (i = 0; i < argc; i++){
printf("%s\n",argv[i]);
}

return 0;  //C语言程序异常退出的代码，是返回给操作系统的，0表示正常退出
}

C:\Users\Administrator\.CLion12\system\cmake\generated\45b5718a\45b5718a\Debug>C01HelloC.exe //当前应用程序的文件名

C01HelloC.exe //当前控制台所传入的第一个参数

C:\Users\Administrator\.CLion12\system\cmake\generated\45b5718a\45b5718a\Debug>C01HelloC.exe Hello C "Hello World"

C01HelloC.exe

Hello

C

Hello World

3 C语言标准输入与输出

#include <stdio.h>int main() {printf("Hello %d",100);printf("Hello %d\n",50);puts("Hello C");puts("Hello world");char buf[100];gets(buf);puts(buf);int a;scanf("%d",&a);printf("%d\n",a);return 0;}

4 C语言方法调用

#include <stdio.h>int max(int a, int b){if (a>b){return a;}else{return b;}}int main() {printf("%d\n", max(10,12));return 0;}

5 C语言宏定义 – 在编译阶段

#include <stdio.h>

#define MATH_PI 3.14   //在编译阶段进行替换，因此在运行过程中很快

int main() {printf("%f\n", MATH_PI);return 0;}

6 C语言宏方法定义 – 在编译阶段，无类型

#include <stdio.h>#define MAX(A,B) \A>B?A:Bint main() {printf("%d\n",MAX(20,10));return 0;}

7 C语言条件判断

#include <stdio.h>void test(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 test1(int score){switch (score/10) {case 9:puts("优秀");break;case 8:puts("良好");break;case 7:case 6:puts("及格");break;default:puts("不及格");break;}}int max(int a,int b){return a>b?a:b;}int main() {test(88);test1(35);printf("%d", max(20,10));return 0;}

8 C语言循环

#include <stdio.h>int main() {int i,j;for (i = 0; i < 100; i++){printf("%d\n",i);}for (j = 0; j < 100 ; printf("%d\n",j++)) {puts("我先执行");}int k = 0;while (k<100){printf("%d\n",k);++k;}int a = 0;do {printf("%d\n",a);a++;}while (a<100);return 0;}

一般情况，for循环用的最多，while用在死循环中。

9 C语言结构体 – 存储数据的集合 – 结构体的赋值，直接是内存的拷贝

#include <stdio.h>struct People{int age;char* name;};int main() {struct People p;p.age = 10;p.name = "yuxiang";printf("age:%d\n",p.age);struct People p1 = p;  //内存的拷贝
p.age = 20;printf("age:%d\n",p1.age);return 0;}

10 C语言结构体指针 - 同一块内存

#include <stdio.h>#include <stdlib.h>struct People {int age;};int main() {struct People *p = malloc(sizeof(struct People));p->age = 10;printf("%d\n",p->age);struct People *p1 = p;  //p1和p指向同一块内存
p1 -> age = 20;printf("%d\n",p1->age);free(p);return 0;}

11 C语言函数指针

#include <stdio.h>void sayHello(){printf("Hello C\n");}int main() {//    sayHello();void (*p)();  //通过一个函数指针p = sayHello;  //指向sayHello方法p();  //通过指针来执行方法return 0;}

12 C语言typedef关键字

#include <stdio.h>typedef struct {int age;} People;typedef void (*Func)();void sayHello(){printf("type define function\n");}int main() {People p;p.age = 10;printf("%d\n",p.age);Func f = sayHello;f();return 0;}

13 C语言面向对象 – 思维方式

代码一：

typedef struct {int age;void (*sayHello)();} People;void PeopleSayHello(){printf("Hello\n");}People * PeopleCreate(){return malloc(sizeof(People));}void PeopleDelete(People *p){free(p);}People* PeopleInit(People* p,int age){p->age = age;p->sayHello = PeopleSayHello;return p;}int main() {People *p = PeopleInit(PeopleCreate(),20);p->sayHello();PeopleDelete(p);return 0;}

代码二：

#include <stdio.h>
#include <stdlib.h>

//object begin>>>>>>>
#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;
}
//object end<<<<<<<<<

typedef struct {
ObjectField
int age;
void (*sayHello)();
} People;

void PeopleSayHello(){
printf("Hello\n");
}

void PeopleOnDelete(People *p){
ObjectOnDelete(p);
printf("People on delete\n");
}

People* PeopleInit(People* p,int age){
ObjectInit((Object*)p);
p->age = age;
p->sayHello = PeopleSayHello;
p->onDelete = PeopleOnDelete;
return p;
}

int main() {
People *p = PeopleInit(ObjectCreate(People),20);
p->sayHello();
ObjectDelete(p);

return 0;
}

14 C语言引入自定义头文件

//hello.h

#ifndef C13INCLUDE_HELLO_H  //防止头文件重复引入
#define C13INCLUDE_HELLO_H
void sayHello();
#endif //C13INCLUDE_HELLO_H

// hello.c

#include <stdio.h>  //系统库，第三方库
#include "hello.h"  //自定义库

void sayHello(){
printf("Hello C");
}

//main.c

#include "hello.h"

int main() {
sayHello();
return 0;
}

15 C语言字符串操作 - sprintf

#include <stdio.h>
#include <string.h>

int main() {
char buf[100];
memset(buf,0,100);
sprintf(buf,"Hello %d,%f,%s",100,1.2,"yuxiang"); //将格式化的字符串打印到缓冲区中

    printf("%s\n",buf);

return 0;
}

16 C语言文件操作 – fprintf、 fread

#include <stdio.h>


int main() {
//    int i;
//    FILE *f = fopen("data.txt","w");
//    if (f!=NULL) {
//        for (i=0; i<100; i++){
//            fprintf(f,"Hello %d\n",i);
//        }
//    }
//    fclose(f);

FILE *f = fopen("data.txt","r");
fseek(f,0,SEEK_END);
long size = ftell(f);
char buf[size+1];
fseek(f,0,SEEK_SET);
fread(buf, sizeof(unsigned char),size,f);
buf[size] = '\0';
fclose(f);

printf("%s",buf);

return 0;
}

17 C语言实现猜数字小游戏

#include <stdio.h>
#include <time.h>
#include <stdlib.h>


int main() {
srand((int)time(NULL)); //使用当前系统的时间，指定一个随机的种子
    int randNum = rand()%10;

printf("输入一个0到10的数值\n");

int userInput;
while (1){
scanf("%d",&userInput);

if (userInput<randNum) {
printf("数值过小\n");
}else if (userInput>randNum) {
printf("数值过大\n");
}else{
printf("正确\n");
break;
}
}

printf("exit\n");

return 0;
}