4.14.1

#include "stdio.h"
#include <string.h>  
#include <stdlib.h>  
#define MAX 1000
int main(void)    
{  
   int i = 2;
   float last ,next = 1.0;
   float n;
   puts("请输入一个正数: ");
   scanf( " %f",&n );
   if(n < 0)
   {
   	printf("输入不正确!\n");
   	exit( EXIT_FAILURE); 
   }
   do{
   	last = next;
   	next = ( last + n / last ) / 2;
   	printf("第%d次接近为：%f\n",i++, next);
   }while(next != last);
   printf("%f的平方根为%f\n",n,next);
   return 0;    
}