经典算法_字符串

 1 #define _CRT_SECURE_NO_WARNINGS
 2 
 3 #include<stdio.h>
 4 #include<stdlib.h>
 5 #include<string.h>
 6 
 7 void mystrncat(char *bc, char *c, int length)
 8 {
 9     if (bc == NULL || c == NULL)
10     {
11         return NULL;
12     }
13     else
14     {
15         int i;
16         char *p = bc;
17         while (*p != ‘\0‘)
18         {
19             p++;
20         }
21         //p指向了字符串的末端‘\0‘
22         for (i = 0;i < length;i++)//前进length个字符
23         {
24             *p = c[i];//赋值
25             p++;//指针前进，遍历
26         }
27     }
28 }
29 
30 main()
31 {
32     char str[30] = "task";
33     char str1[30] = "list8848";
34 
35     puts(str);
36 
37     mystrncat(str, str1, 4);
38 
39     puts(str);
40 
41     system(str);
42 
43     system("pause");
44 }