code.c++

code.c++/P1/P1.cpp

@@ -0,0 +1,19 @@
+// P1.cpp : �������̨Ӧ�ó������ڵ㡣
+//
+
+#include "stdafx.h"  
+#include "iostream"
+using namespace std;
+int main()
+{
+	double n;
+	cin>>n;
+	double p,i;
+	for(i=1; i<=n; i++)
+	{
+		 p=1/n;
+		 cout<<p<<" ";
+	}
+	return 0;
+}
+

code.c++/P12/P12.cpp

@@ -0,0 +1,33 @@
+// P12.cpp : �������̨Ӧ�ó������ڵ㡣
+//
+
+#include "stdafx.h"
+#include "iostream"
+#include "string"
+using namespace std;
+
+void main()
+{
+	float pCan = 0.001;
+	float pNon = 0.999;
+	float pPosCan = 0.8;
+	float pPosNon = 0.1;
+	float px,py;
+	string z;
+	cin>>z;
+	if(z=="positive")
+	{
+		px = pPosCan*pCan;
+		py = pPosNon*pNon;
+	}
+	else if(z=="negative")
+	{
+		px = (1-pPosCan)*pCan;
+		py = (1-pPosNon)*pNon;
+	}
+	px=px/(px+py);
+	py=py/(px+py);
+	cout<<"p(1)="<<px<<endl;
+	cout<<"p(2)="<<py<<endl;
+}
+

code.c++/P13/P13.cpp

@@ -0,0 +1,40 @@
+// P13.cpp : �������̨Ӧ�ó������ڵ㡣
+//
+
+#include "stdafx.h"
+#include "iostream"
+#include <cmath>
+using namespace std;
+
+double compMean(int x[],int n)
+{
+	double sum = 0;
+	for(int i=0;i<n;i++)
+	{
+		sum += x[i];
+	}
+	double mu = sum/n;
+	return mu;
+}
+
+double compVariance(int x[],int n,double mu)
+{
+	double sum = 0;
+	for(int i=0;i<n;i++)
+	{
+		sum += pow((x[i]-mu),2);
+	}
+	double sigma2 = sum/n;
+	return sigma2;
+}
+
+int main()
+{
+	int x[5]={7,38,4,23,18};
+	double mu = compMean(x,5);
+	double sigma2 = compVariance(x,5,mu); 
+	cout<<"The Expectation / Mean is:"<<mu<<endl;
+	cout<<"The Variance is:"<<sigma2<<endl;
+	cout<<"The Standard Deviation is:"<<sqrt(sigma2)<<endl;
+	return 0;
+}

code.c++/P14/P14.cpp

@@ -0,0 +1,35 @@
+// P14.cpp : �������̨Ӧ�ó������ڵ㡣
+//
+
+#include "stdafx.h"
+#include "iostream"
+#include <cmath>
+using namespace std;
+
+double compMean(int x[],int n)
+{
+	double sum = 0;
+	for(int i=0;i<n;i++)
+	{
+		sum += x[i];
+	}
+	double mu = sum/n;
+	return mu;
+}
+
+int main()
+{
+	int a = 2;
+    int b = 4;
+	int x[5]={7,38,4,23,18};
+	int y[5];
+	for(int i=0;i<5;i++)
+	{
+		y[i] = a*x[i]+b;
+	}
+	double xmu = compMean(x,5);
+    double ymu = compMean(y,5);
+	cout<<"a*Xmu+b="<<a*xmu+b<<endl;
+	cout<<"Ymu="<<ymu<<endl;
+	return 0;
+}

code.c++/P15/P15.cpp

@@ -0,0 +1,45 @@
+// P15.cpp : �������̨Ӧ�ó������ڵ㡣
+//
+
+#include "stdafx.h"
+#include "iostream"
+#include <cmath>
+using namespace std;
+
+double compMean(int x[],int n)
+{
+	double sum = 0;
+	for(int i=0;i<n;i++)
+	{
+		sum += x[i];
+	}
+	double mu = sum/n;
+	return mu;
+}
+
+double compVariance(int x[],int n,double mu)
+{
+	double sum = 0;
+	for(int i=0;i<n;i++)
+	{
+		sum += pow((x[i]-mu),2);
+	}
+	double sigma2 = sum/n;
+	return sigma2;
+}
+
+int main()
+{
+	int x[5]={7,38,4,23,18};
+	int x2[5];
+	double xmu = compMean(x,5);
+	for(int i=0;i<5;i++)
+	{
+		x2[i] = pow(x[i],2);
+	}
+	double x2mu = compMean(x2,5);
+	double xvar = compVariance(x,5,xmu); 
+	cout<<"The Variance of X is:"<<xvar<<endl;
+	cout<<"E[X^2]-E[X]^2="<<x2mu-pow(xmu,2)<<endl;
+	return 0;
+}

code.c++/P2/P2.cpp

@@ -0,0 +1,73 @@
+// P2.cpp : �������̨Ӧ�ó������ڵ㡣
+//
+
+#include "stdafx.h"
+#include "iostream"
+#include "string"
+using namespace std;
+
+double sum1(string world[],int n,double wd[])
+{
+	double sum = 0;
+	double red = 0.6;
+	double green = 0.2;
+	for(int i=0;i<n;i++)
+	{
+		if(world[i] == "red")
+		{
+			wd[i] = red*1/n;
+		}
+		else if(world[i] == "green")
+		{
+			wd[i]=green*1/n;
+		}
+		sum += wd[i];
+	}
+	return sum;
+}
+
+double sum2(string world[],int n,double wd[])
+{
+	double sum = 0;
+	double red = 0.2;
+	double green = 0.6;
+	for(int i=0;i<n;i++)
+	{
+		if(world[i] == "red")
+		{
+			wd[i] = red*1/n;
+		}
+		else if(world[i] == "green")
+		{
+			wd[i]=green*1/n;
+		}
+		sum += wd[i];
+	}
+	return sum;
+}
+
+void main()
+ {
+	string name;
+	cin>>name;
+	string world[5]={"green","red","red","green","green"};
+	double wd[5];
+	double p1[5];
+	double p2[5];
+    if(name=="red")
+	{
+		for(int i=0;i<5;i++)
+	   {
+		 p1[i] = wd[i]/sum1(world,5,wd);
+		 cout<<p1[i]<<" ";
+	   }
+	}
+	else if(name=="green")
+	{
+		for(int i=0;i<5;i++)
+	   {
+		 p2[i] = wd[i]/sum2(world,5,wd);
+		 cout<<p2[i]<<" ";
+	   }
+	}
+ }