12個滑稽的C語言面試問答——《12個有趣的C語言問答》評析(4)

 

 

#include<stdio.h>

int main(void)
{
    char *ptr = "Linux";
    *ptr = 'T';

    printf("\n [%s] \n", ptr);

    return 0;
}

 

 

Q:你能否寫一個程序在它運行時修改它的名稱？ (Can you write a program that changes its own name when run?)

 

#include<stdio.h>

int main(int argc, char *argv[])
{
    int i = 0;
    char buff[100];

    memset(buff,0,sizeof(buff));

    strncpy(buff, argv[0], sizeof(buff));
    memset(argv[0],0,strlen(buff));

    strncpy(argv[0], "NewName", 7);

    // Simulate a wait. Check the process
    // name at this point.
    for(;i<0xffffffff;i++);

    return 0;
}

 

 

 int i = 0;
　　//……
 for(;i<0xffffffff;i++);

 

for ( i = 0 ; i < 0xffffffff ; i ++ )
   ;

    char buff[100];

    memset(buff,0,sizeof(buff));

    strncpy(buff, argv[0], sizeof(buff));
    memset(argv[0],0,strlen(buff));

       strncpy(argv[0], "NewName", 7);

 

　　memset(buff,0,sizeof(buff));

 

　　strncpy(buff, argv[0], sizeof(buff));

 

   char s[4];
   strncpy( s , "1" , 4);
   printf("%d %d %d %d\n",s[0],s[1],s[2],s[3]);

  49 0 0 0

memset(argv[0],0,strlen(buff));

memset(argv[0],0,strlen(argv[0]));

 

strncpy(argv[0], "NewName", 7);