面试题汇集（更新中）

来源：互联网发布：中国高等植物数据库编辑：程序博客网时间：2024/06/11 08:09

1，求较小和较大的值，不能用比较运算符 if-else ?: while for 内嵌汇编递归第三方函数
int Min(int a, int b) int Min(int a, int b)
{ ｛

//write code here //write code here
} ｝
解答：

int max = ((a+b)+abs(a-b))/2

int min((a+b)-abs(a-b))/2;

2，写atol()函数

#include <stdio.h>
int main()
{
   unsigned char *nptr;
   char a[] =" -12345";
   int c; /* current char */
   long total; /* current total */
   int sign; /* if '-', then negative, otherwise positive */

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

   c = (int)(unsigned char)*nptr++; /*符号*/
   sign = c; /* save sign indication */
   if (c == '-' || c == '+'){
        c = (int)(unsigned char)*nptr++; /* skip sign */
       printf("%d\n",c);
   }
   total = 0;

   while (isdigit(c)) {
        total = 10 * total + (c - '0'); /* accumulate digit */
        c = (int)(unsigned char)*nptr++; /* get next char */
   }
     if (sign == '-'){
       total = -total;
       printf("total = %d\n",total);
   }else
        //return total; /* return result, negated if necessary */
       printf("total = %d\n",total);
   return 0;
}