strcpy() 使用失败

  
    

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

   
     #define
   
      NL 100
   
     


   
     int
   
      main()
{
 
   
     char
   
      s0[NL], s1[NL];
 memset(s0, 
   
     0
   
     , 
   
     sizeof
   
     (s0));
 memset(s1, 
   
     0
   
     , 
   
     sizeof
   
     (s1));
 s0[
   
     1
   
     ] 
   
     =
   
      
   
     1
   
     ;
 strcpy(s1, s0);
 
   
     return
   
      
   
     0
   
     ;
}
  
    

 

拷贝的结果是：s1 = ""，s1[1] = 0;

分析：strcpy()函数的功能是字符串拷贝，而字符串是以/0为结束标志。所以简单的把strcpy()当成数组的拷贝是错误的想法。

参考：

strcpy

function

<cstring>

char * strcpy ( char * destination, const char * source );

Copy string

Copies the C string pointed by source into the array pointed by destination, including the terminating null character.

 

To avoid overflows, the size of the array pointed by destination shall be long enough to contain the same C string as source (including the terminating null character), and should not overlap in memory with source.

 

Parameters

destination

Pointer to the destination array where the content is to be copied.

source

C string to be copied.

 

 

Return Value

destination is returned.

 

 

Example

   
     

    
      
    
      /*
    
       strcpy example 
    
      */
    
      
#include 
    
      <
    
      stdio.h
    
      >
    
      
#include 
    
      <
    
      string
    
      .h
    
      >
    
      

 


    
      int
    
       main ()
{

    
      　　char
    
       str1[]
    
      =
    
      "
    
      Sample string
    
      "
    
      ;

    
      　　char
    
       str2[
    
      40
    
      ];

    
      　　char
    
       str3[
    
      40
    
      ];
　　strcpy (str2,str1);
　　strcpy (str3,
    
      "
    
      copy successful
    
      "
    
      );
　　printf (
    
      "
    
      str1: %s\nstr2: %s\nstr3: %s\n
    
      "
    
      ,str1,str2,str3);

    
      　　return
    
       
    
      0
    
      ;
}
   
     

 

 

Output:

str1: Sample string
str2: Sample string
str3: copy successful