string之strlen

#include <string.h>

       size_t strlen(const char *s);

#include <stddef.h>
#include <stdio.h>

size_t myStrlen(char const *s);

int
main(void)
{
        char *s = "hello";
        char *t = "me";

        printf("%d\n", myStrlen(s));
        printf("%d\n", myStrlen(t));

        if (myStrlen(s) >= myStrlen(t))
                printf("s > t\n");

        if (myStrlen(s) - myStrlen(t) >= 0)
                printf("s > t\n");
/*
 * size_t 为无符号类型，size_t - size_t 也为无符号类型， 永远>=0
 */
        if (myStrlen(t) - myStrlen(s) >= 0)
                printf("t > s\n");

        if (myStrlen(t) - 100 >= 0)                printf("t > 100\n");        if (myStrlen(t) - 1 >= 0)                printf("t > 1\n");

        return 0;
}

size_t
myStrlen(char const *s)
{
        int len;

        for (len = 0; *s++ != '\0'; len++)
                ;

        return (len);
}

Result:

5
2
s > t
s > t
t > s
t > 100
t > 1