牛顿拉普森迭代法

 

//计算某数的平方根
   #include <stdio.h>

   float absoluteValue(float x)
   {
       if(x<0)
       {
           x=-x;
       }
       return x;
   }

   //计算某数平方根的函数
   float squareRoot(float x)
   {
       const float epsilon=.00001;
       float guess=1.0;

       while(absoluteValue(guess*guess-x)>=epsilon)
       {
           guess=(x/guess+guess)/2.0;
       }
       return guess;
   }

   int main()
   {
       float num;
       printf("输入要求平方根的数：");
       scanf("%f",&num);
       printf("%f平方根是%f\n",num,squareRoot(num));
       return 0;
   }