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Pointer initialization

2022-07-02 08:25:00 【kq1983】


initialization

Pointer initialization :    Address of a variable Memory address Or string constants perhaps NULL


Address of a variable 

       

        int i= 10;
        
int *p2 = &i; // Statement 1 A pointer to the p2, And directly initialize it as a variable i Value 
        

        

        

        
char letter = 'L';
        
char *myLetter = &letter; //  Statement 1 Pointer variables myLetter  And directly initialize to letter The address of 
       

       
    
        
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Memory address 

       

        char * name = (char*)malloc(10);  // Statement 1 Character pointer name
        
strcpy(name, "abcde123456");
        

        
printf("name=%s \n",name);
       

       
    
        
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String constant 

       

        char * mystr = "welcome to c!"; //  String constant 
       

       
    
        
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NULL

NULL The address does not exist in memory , yes 0 Address 

       

        int *p1 = NULL;//  Declare pointer variables p1, And initialize to NULL
       

       
    
        
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Wild pointer 

       

        char *p;
        
printf("p=%c \n",*p); //  Will report a mistake 
       

       
    
        
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The wrong case

# *p    p Must be a valid address , Otherwise, the program will crash

Wild pointer 

       

        char *p;
        
printf("p=%c \n",*p);
       

       
    
        
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NULL

       

        char *p = NULL;
        
printf("p=%s \n",*p);
       

       
    
        
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本文为[kq1983]所创，转载请带上原文链接，感谢
https://yzsam.com/2022/02/202202151742409885.html

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