strncpy ()- 复制字符串

在线编辑

格式

#include <string.h>
char *strncpy(char *string1, const char *string2, size_t count);

语言级别

ANSI

线程安全

是

描述

strncpy() 函数将 string2 的 count 个字符复制到 string1。 如果 count 小于或等于 string2的长度，那么 不会 向复制的字符串追加空字符 (\0)。 如果 count 大于 string2的长度，那么将使用空字符 (\0) 填充 string1 结果，最大长度为 count。

返回值

strncpy() 函数返回指向 string1的指针。

示例

此示例演示 strcpy() 与 strncpy()之间的差异。
#include <stdio.h>
#include <string.h>
 
#define SIZE    40
 
int main(void)
{
  char source[ SIZE ] = "123456789";
  char source1[ SIZE ] = "123456789";
  char destination[ SIZE ] = "abcdefg";
  char destination1[ SIZE ] = "abcdefg";
  char * return_string;
  int    index = 5;
 
  /* This is how strcpy works */
  printf( "destination is originally = '%s'\n", destination );
  return_string = strcpy( destination, source );
  printf( "After strcpy, destination becomes '%s'\n\n", destination );
 
 
  /* This is how strncpy works */
  printf( "destination1 is originally = '%s'\n", destination1 );
  return_string = strncpy( destination1, source1, index );
  printf( "After strncpy, destination1 becomes '%s'\n", destination1 );
}
 
/*****************  Output should be similar to:  *****************
 
destination is originally = 'abcdefg'
After strcpy, destination becomes '123456789'
 
destination1 is originally = 'abcdefg'
After strncpy, destination1 becomes '12345fg'
*/

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