n阶勒让德多项式求解

    n阶勒让德多项式的定义是递归的进行定义，所以求解，也需要进行递归的求解。代码如下：

#include <stdio.h>

float rand(int n, float x)
{
  if(n == 0)  return 1;
  else if(n == 1)  return x;
  else return ((2 * n) * x - rand(n-1, x) - (n - 1) * rand(n-2, x)) / n;
}

int main(int argc, char *argv[])
{
  int n;
  float x,p;
  printf("please input n\n");
  scanf("%d",&n);
  printf("please input x\n");
  scanf("%f",&x);
  p = rand(n,x);
  printf("the result of P%d(%f) = %f\n",n,x,p);
  return 0;
}