shuzhifenxi.rar_visual c

#include<iostream> #include<iomanip> #include<string> using namespace std; double f(double t1,double t2) { double y; y=t1*t2; return y; } double cx(double x) { double y; y=x; return y; } double dx(double x) { double y; y=2*x; return y; } double Dblint(double a,double b,double m,double n) { double s1,s2,s3,k1,k2,k3; double h,S,L,G; double x,y,z; h=(b-a)/(2*n); cout<<"h="<<h<<endl; s1=0; s2=0; s3=0; cout<<"----------------------------------------------------------------"<<endl; for(int i=0;i<=2*n;i++) { x=a+i*h; G=(dx(x)-cx(x))/(2*m); k1=f(x,cx(x))+f(x,dx(x)); cout<<setprecision(7); cout<<"k1="<<k1<<setw(8)<<"G="<<G<<endl; k2=0; k3=0; for(int j=1;j<=(2*m-1);j++) { y=cx(x)+j*G; z=f(x,y); if(j%2==0) { k2=k2+z; } else { k3=k3+z; } } L=(k1+2*k2+4*k3)*(G/3); if(i==0||i==2*m) { s1=s1+L; } else if(i%2==0) { s2=s2+L; } else { s3=s3+L; } } S=(s1+4*s3+2*s2)*(h/3); return S; } int main() { double a,b,m,n,S; cout<<"请输入区间a,b和等分数m,n:"<<endl; cin>>a>>b>>m>>n; S=Dblint(a,b,m,n); cout<<"输出二重积分值:"<<flush; cout<<"S="<<S<<endl; return 0; }