C经典库函数：字符串反转、字符转长整型与判断是否为数字

1.//**************************************************************************************
char* reverse(char* Array)
{
int len = strlen(Array);
for(int i=0;i<len/2;i++)
{
char temp=*(Array+i);
*(Array+i)=*(Array+len-1-i);
*(Array+len-1-i)=temp;
}
*(Array+len)='\0';
return Array;
}
2.//**************************************************************************************
long __cdecl atol(
        const char *nptr
        )
{
        int c;              /* current char */
        long total;         /* current total */
        int sign;           /* if '-', then negative, otherwise positive */

        /* skip whitespace */
        while ( isspace((int)(unsigned char)*nptr) )
            ++nptr;

        c = (int)(unsigned char)*nptr++;
        sign = c;           /* save sign indication */
        if (c == '-' || c == '+')
            c = (int)(unsigned char)*nptr++;    /* skip sign */

        total = 0;

        while (isdigit(c)) {
            total = 10 * total + (c - '0');     /* accumulate digit */
            c = (int)(unsigned char)*nptr++;    /* get next char */
        }

        if (sign == '-')
            return -total;
        else
            return total;   /* return result, negated if necessary */
}
3.//**************************************************************************************
判断一个链表是否为循环链表(追赶法)
bool isLoop(link *head)
{
link *p = head;
link *q = head;
while(p != NULL && q != NULL && q->next != NULL)
{
p = p->next;
q = q->next->next;
if(p == q)
return true;
}
return false;
}
4.//**************************************************************************************
char * __cdecl strchr (