#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
//函数指针
#if 0
//void test(char **p){
//
//}
char *mymalloc(char **p)
{
static char a[100];
*p= a;
}
int main(){
//char arr[] = "darqfafafa";
/*char *arr[5] = { "ad", "dada", "dasfa", "fasfaq", "daafa" };
test(arr);
test(&arr[0]);*/
char *str = NULL;
mymalloc(&str);
strcpy(str, "hollow world");
puts(str);
system("pause");
return 0;
}
#endif
#if 0
int main(){
char arr[] = { 1, 2, 3, 4, 5, 6 };
printf("%d\n", strlen(&arr + 1));
system("pause");
return 0;
}
#endif
#if 0
int main(){
int a = 6;
int *p = &a;
printf("%p\n", p);
printf("%p\n", p + 0x1);
printf("%p\n", (unsigned long)p + 0x1);
printf("%p\n",(short*)p+0x1);
printf("%p\n",(double*)p+0x1);
system("pause");
return 0;
}
#endif
#if 0
int main(){
int a[]={1,2,3,4};
printf("%d\n",sizeof(a));//16
printf("%d\n",sizeof(a+0));//4
printf("%d\n",sizeof(*a));//4
printf("%d\n",sizeof(a+1));//4
printf("%d\n",sizeof(a[1]));//4
printf("%d\n",sizeof(&a));//4
printf("%d\n",sizeof(*&a));//16
printf("%d\n",sizeof(&a+1));//4
printf("%d\n",sizeof(&a[0]));//4
printf("%d\n",sizeof(&a[0]+1));//4
system("pause");
return 0;
}
#endif
#if 0
int main(){
char arr[]={'a','b','c','d','e','f'};
printf("%d\n",sizeof(arr));
printf("%d\n",sizeof(arr+0));
printf("%d\n",sizeof(*arr));
printf("%d\n",sizeof(arr[1]));
printf("%d\n",sizeof(&arr));
printf("%d\n",sizeof(&arr[0]+1));
system("pause");
return 0;
}
#endif
#if 0
int main(){
char *c[]={"ENTER","NEW","POINT","FIRST"};
char **cp[]={c+3,c+2,c+1,c};
char ***cpp=cp;
printf("%s\n",**++cpp);
printf("%s\n",*--*++cpp+3);
printf("%s\n",*cpp[-2]+3);
printf("%s\n",cpp[-1][-1]+1);
system("pause");
return 0;
}
#endif
#if 0
//字符串操作函数：strlen ......
int main(){
char a[10] = { 'a', 'b', 'c', 'd', 'e' };//告诉数组的大小之后才能知道长度
char b[] = { 'a', 'b', 'c', 'd', 'e' };//也就是才能找到/0，/0会补充这个数组没有的部分
char c[] = "123456";
char str[] = "abc\012abc";//abc\nabc
char str1[] = "abc\0abc";//abc0abc
int n, m, z;
n = strlen(a);//5
m=strlen(b);//>5
z=strlen(c);//6
printf("%d,%d,%d\n",n,m,z);
n = strlen (str);//7
m = strlen(str1);//3
printf("%d,%d\n", n, m);
system("pause");
return 0;
}
#endif
#if 0
//strcpy:把这个字符串的自身的元素和自身的 一个 \0拷贝到第一个参数里面
//char *strcpy(char *dest,const char *source) 链式表达式
int main(){
char a[20] = "12345678";
char b[20] = "qwer";
strcpy(a, b);
printf("%s\n", a);
system("pause");
return 0;
}
#endif
#if 0
//strcat:拼接函数
//char *strcat(char *dest, const char *source)
int main(){
char a[20] = "12345678";
char b[20] = "qwer";
strcat(a, b);
printf("%s\n", a);
system("pause");
return 0;
}
#endif
#if 0
//strcmp:字符串比较大小:按照字符串从首字母开始的ASCII值比较，知道找到不相等的为止
//int strcmp(const char * string1,const char *string2)
int main(){
char a[20] = "12345678";
char b[20] = "qwer";
int n=strcmp(a, b);
printf("%d\n",n);
system("pause");
return 0;
}
#endif
#if 0
//strtok:在字符串中查找标记,并用\0结尾，返回指向这个标记的指针
int main(){
char str[]="i,am.a student";
char sep[]=",. ";
char *tok=NULL;
for (tok=strtok(str,sep);tok!=NULL;tok=strtok(NULL,sep)){
puts(tok);
}
system("pause");
return 0;
}
#endif
#if 0
int main(){
system("pause");
return 0;
}
#endif
total: Significance array name:
1.sizeof (array name), the name of the array where the entire array representation, the calculated size of the entire array
2. & array name, where the name of the array represents the entire array, the entire array is extracted address
3. in addition to all of the names array represents the address of the first element