常见函数strlen仿写

 1 #include <stdio.h>
 2 #include <stdlib.h>
 3 #include <string.h>
 4 
 5 
 6 //while
 7 //do while
 8 //for
 9 //递归
10 //goto
11 
12 //仿写strlen 用数组的方式
13 size_t strlength1(const char * arr)
14 {
15     int length = 0;
16     for (int i = 0;; i++)
17     {
18         if (arr[i] == '\0')
19         {
20             break;
21         }
22         length++;
23     }
24     return length;
25 }
26 
27 
28 
29 //仿写strlen 用指针的方式
30 size_t strlength2(const char* arr)
31 {
32     int length = 0;
33     for (char *i = arr; *i != '\0'; i++)
34     {
35         length++;
36     }
37     return length;
38 }
39 
40 
41 
42 //strlen();
43 int main1(void)
44 {
45     char str[100] = "Calc";
46     int length = strlength2(str);
47     printf("%d\n", length);
48 
49     system("pause");
50     return 0;
51 }