C language pointer bit 1

1#include <stdio.h>2#include <stdlib.h>3 4 voidMain ()5 {6     int*p = NULL;//The pointer starts preferably initialized to null7     if(p = =NULL)8     {9printf"Sister P is now single can be a crazy offense");Ten}Else One     { Aprintf"sister P is not single please think carefully"); -     } -     //printf ("%d", *p);//illegal 0x000000 operating system use can not play casually the  - GetChar (); -}

1#include <stdio.h>2#include <stdlib.h>3 4 voidmain1 ()5 {6     intnum = -;7     int*p;//the error uses an uninitialized local variable8     //in some C + + compilers do not check the initialization of variables, pointers must be initialized before use9     //p = num;//relative to the 100 address given P can compile cannot runTenp = &num; Oneprintf"%d",*p); Aprintf"%x",&p); -  -  the GetChar (); -}

1#include <stdio.h>2#include <stdlib.h>3 4 voidmain4 ()5 {6     DoubleA =1, b=2, c=3;//Double8 bytes7     //double *pa,pb,pc;//Pointer four bytes PA is pointer8     Double*pa,*pb,*pc;9printf"%d%d%d",sizeof(PA),sizeof(PB),sizeof(PC));Ten}

C language pointer bit 1