拉格朗日-牛顿插值程序

// Note:Your choice is C++ IDE #include <iostream> using namespace std; int main() { int i,j; int n; float m; printf("please input n:\n"); scanf("%d",&n); float a[20][2]; //= {{0.4,0.41075},{0.55,0.57815},{0.8,0.88811},{0.9,1.02652},{1,1.17520}}; float x,y; printf("please input each point's values\n"); for(i = 0;i < n + 1;i++) { printf("x_%d\n",i); scanf("%f",a[i]); printf("y_%d\n",i); scanf("%f",a[i] + 1); } printf("please input x value\n"); scanf("%f",&x); y = 0; for(i = 0;i< n+1;i++) { m = 1; for(j = 0;j< n+1;j++) { if(i == j) { ; } else { m *= (x-a[j][0])/(a[i][0] - a[j][0]); } } y += m*a[i][1]; } printf("%f",y); return 0; }