C语言九阴真经

来源：互联网发布：linux系统分区方案编辑：程序博客网时间：2024/04/29 15:39

发现记忆力越来越差，所以干脆搞这么一个东西，就是把C语言的最常用的语法汇编在一起，不断完善。这样以后只要经常把这个回顾一下就可以了。不然去翻书太多了。。。

f.h

#define Area 1000  struct student{char *last_name;int student_id;char grade;int a;};

h.c

#include <stdio.h> #include "f.h"#define PI 3.1415926#define LIMIT 20struct employee_data{int a;};int main(void){//引用printf("%d\n",Area);//字符char c;c='A';int age;char first,end;printf("%c\n",c);printf("%3c\n",c);printf("%3c\n",'A');//scanf("%d",&age);//printf("%d\n",age);//scanf("%c",&first);//printf("%c\n",first);char *p1;p1=&c;printf("%c%d%c\n",*p1,*p1+1,*p1+2);//printf("%c",'\a');//响铃//char d=getchar();//putchar()//printf("%c\n",d);const int p_sea=20;//p_sea=30;会报错，向只读变量赋值float x,y;x=2.0;y=3.0;printf("%f\n",x*y);printf("%f\n",PI);double d1=1.123456789;printf("%lf\n",d1);int i=1,sum=0;while (i<7){sum=sum+i;i++;}printf("%d\n",sum);int sz[3]={23,15,78};sz[1]=2;printf("%d\n",sz[1]);//求数组长度int count=sizeof(sz)/sizeof(int);  printf("%d\n",count);typedef int myint;myint i1=9;printf("%d\n",i1);printf("%d\n",sizeof(i1));//输出4 int是4位//指针和数组关系int sz1[4]={40,82,67,11};int *p;p=sz1;printf("*p %d\n",*p);//40printf("*p+1 %d\n",*p+1);//41printf("*p+2 %d\n",*p+2);//42printf("*p %d\n",*p);//40printf("*p+1 %d\n",*(p+1));//82printf("*p+2 %d\n",*(p+2));//67struct card{int pips;char suit;}c1,c2;c1.pips=3;c1.suit='5';c2=c1;printf("struct c2.pips: %d\n",c2.pips);typedef struct{int re;int im;}complex;complex as,ac[2];as.re=89;ac[0].re=1;ac[1].re=2;printf("struct ac[0].re: %d\n",ac[0].re);printf("struct ac[1].re: %d\n",ac[1].re);printf("struct ac[0].re: %d\n",ac[0].re);struct student tmp;tmp.last_name="Canada";tmp.grade='A';tmp.student_id=122;tmp.a=0;printf("struct tmp.last_name: %s\n",tmp.last_name);struct employee_data e1;e1.a=12;int e11=getdata(e1);printf("struct e11: %d\n",e11);int e12=getdata_add(&e1);printf("struct e12: %d\n",e12);//与或非int y1=3;int y2=0;int y3=y1&y2;printf("y3 &: %d\n",y3);printf("-9 >>31: %d\n",abs(-9));#undef __FD_SETSIZE#define __FD_SETSIZE    1024printf("#define: %d\n",__FD_SETSIZE);return 0;}//一个负数右移31位后会变成 0xffffffff，一个正数右移31位则为 0x00000000//0xffffffff ^ a + a = - 1//因为 1011 ^ 1111 = 0100 异或1111其实是把a的0和1进行了颠倒。int abs(int x){    return (x ^ (x >> 31)) - (x >> 31);}int getdata(struct employee_data e){return e.a;}int getdata_add(struct employee_data *e){return e->a;}