C++編写数值分析程序.doc

高斯消去法； #include iostream using namespace std; template class T T** Allocation2D(int m, int n) { T **a; a = new T*[m]; for (int i=0; im; i++) { a[i] = new T[n]; } return a; } int main() { int i,j,k; int n; float** a; cout输入系数矩阵的N值，N：; cinn; a = Allocation2Dfloat(n, n+1); coutendl输入增广矩阵的各值：/n; for(i=0; in; i++) { for(j=0; jn+1; j++) { cina[i][j]; } } for(k=0; kn-1; k++) { for(i=k+1; in; i++) { for(j=k+1; jn+1; j++) { a[i][j] = a[i][j] - a[i][k] * a[k][j] / a[k][k]; } } } float temp; a[n-1][n] = a[n-1][n] / a[n-1][n-1]; for(k=n-2; k=0; k--) { temp = 0; for(j=k+1; jn; j++) { temp = temp + a[k][j] * a[j][n]; } a[k][n] = (a[k][n] - temp) / a[k][k]; } for(i=0; in; i++) { coutxi: a[i][n]endl; } return 0; } 拉格朗日插值法 #includeiostream #includemath.h #define N 3 using namespace std; double fun(double *x,double *y, int n,double p); void main() { int i; double a[N],p; double b[N]; coutplease input xiangliang a= endl; for(i=0;iN;i++) {cina[i];} coutplease input xiangliang b= endl; for(i=0;iN;i++) {cinb[i];} coutplease input LagelangrichazhiJieDian p= endl; cinp; coutThe Answer= fun(a,b,N,p)endl; } double fun(double x[],double y[], int n,double p) { double z=0,s=1.0; int k,i=0; double L[N]; k=0; while(kn) { if(k==0) { for(i=1;in;i++) { s=s*(p-x[i])/(x[0]-x[i]); } L[0]=s*y[0]; k=k+1; } else { s=1.0; for(i=0;i=k-1;i++) { s=s*((p-x[i])/(x[k]-x[i])); } for(i=k+1;in;i++) { s=s*((p-x[i])/(x[k]-x[i])); } L[k]=s*y[k]; k++; } } for(i=0;in;i++) { z=z+L[i]; } return z; } Newton插值法； #include iostream.h #include math.h void main() { char L; do { double M[100][100]; double x[100],y[100]; double X=1,xx=0,w=1,N=0,P,R=1; int n; cout请输入所求均差阶数：; cinn; for(int i=0;i=n;i++) { cout请输入xi的值：endl; cinx[i]; cout请输入yi的值：endl;