Write your own strcat function

1:  int my_strcat(char *dst,char *src)  
2:  {  
3:    while(*dst != '\0')  
4:      dst++;  
5:    while(*src != '\0')  
6:      *dst++ = *src++;  
7:    *(dst+1) = '\0';  
8:  }  
9:  main()  
10:  {  
11:    char str1[100] = "hello";  
12:    char str2[100] = "world";  
13:    my_strcat(str1,str2);  
14:    printf("%s\n",str1);  
15:  }