第五章作业part1

一.调试分析课本每一个例题，有可能的话更改成2-3个方法的新程序

例一.

#include<iostream>using namespace std;void display(){    cout<<"This is an example."<<endl;}int main(){    display();    return 0;}

例二

#include<iostream>using namespace std;double min(double x,double y){    return x<y?x:y;}int main(){    cout<<min(6.0,5.0);    return 0;}

例三

#include<iostream>using namespace std;double circleArea(double);int main(){    double area = circleArea(5.0);cout<<"area = "<<area<<endl;return 0;}double circleArea(double r){    double pi=3.14;double area = pi*r*r;    return area;}

例四

#include<iostream>using namespace std;int sum(int x,int y){    int temp;temp = x+y;return temp;}int main(){    int a,b,c;a=10;b=5;    c=sum(a,b);    cout<<a<<"+"<<b<<" = "<<c<<endl;    return 0;}

例五

#include<iostream>using namespace std;int ncomp(int i,int j){    if(i>j)return 1;    if(i==j)return 0;return -1;}int main(){    int k=2;int n=ncomp(k,k++);cout<<n;       return 0;}

例六

#include<iostream>using namespace std;int max(int u,int v){    int w;w=u>v?u:v;return w;}int main(){     int a,b,c; cout<<"please input two number:"; cin>>a>>b; c=max(a,b); cout<<"a="<<a<<"b="<<b<<endl; cout<<"Max is"<<c<<endl;     return 0;}

例七

#include<iostream>using namespace std;int sqr(int x){    x=x*x;return x;}int main(){   int t=10;   int s=sqr(t);   cout<<"t="<<t<<'\t'       <<"sqr"<<t<<")="<<s<<endl;   return 0;}

例八

#include<iostream>using namespace std;void swap(int&u,int &);int main(){    int a=3;int b=4;cout<<"a ="<<a<<"\tb ="<<b<<endl;swap(a,b);cout<<"a ="<<a<<"\tb ="<<b<<endl;return 0;}void swap(int u,int v){    int temp = v;v=u;u=temp;}

例九

#include<iostream>using namespace std;void swap(int&u,int &);int main(){    int a=3;int b=4;cout<<"a ="<<a<<"\tb ="<<b<<endl;swap(a,b);cout<<"a ="<<a<<"\tb ="<<b<<endl;return 0;}void swap(int &u,int &v){    int temp = v;v=u;u=temp;}

例十

#include<iostream>using namespace std;void display(int x,float y){   cout<<x<<" "<<y;   return;}int main(){   float a;   int b;   cin>>b>>a;   display(b,a);   return 0;}

例十一

#include<iostream>#include<cmath>using namespace std;void GetRoots(/*in*/double,/*in*/double,/*in*/double,  /*out*/double&,/*out*/double&);//函数GetRoots 用于求一元二次方程的两个根//前三个形参为流入参数，是值的调用，分别用于接收主调函数传递的三个系数值//后两个形参为流出参数，是引用调用，将计算后的两个根回传给主调函数int main(){    double a,b,c;double root1,root2;    cout<<"输入方程的三个系数a,b,c:"<<endl;cin>>a>>b>>c;GetRoots(a,b,c,root1,root2);//a,b,c作为值调用的三个实参，必须要有初始值//root1.root2作为引用调用的两个实参，可以没有初始值cout<<"root1= "<<root1<<"root2 ="<<root2<<endl;return 0;}void GetRoots(/*in*/double a,/*in*/double b,/*in*/double c,  /*out*/double&root1,/*out*/double&root2){    double temp;temp=b*b-4.0*a*c;    root1=(-b+sqrt(temp))/(2.0/a);root2=(-b-sqrt(temp))/(2.0/a);}

例十三

#include<iostream>using namespace std;long f2(int);long f1(int p){    int k;    long r;    k=p*p;    r=f2(k);return r;}long f2(int q){    long fact = 1;    for(int i=1;i<=q;i++)   fact*=i;    return fact;}int main(){    int i;    long sum=0;    for(i=2;i<=3;i++)    sum+=f1(i);    cout<<"sum ="<<sum<<endl;return 0;}

例十四

#include<iostream>#include<cmath>using namespace std;float f(float x);              //求函数的值float root(float x1,float x2);  //求方程的根float point(float x1,float x2); //求与x轴的交点int main(){    float x1,x2,y1,y2,x;    do{    cout<<"请输入根所在的范围:";cin>>x1>>x2;y1=f(x1);y2=f(x2);cout<<"两端点的值为["<<y1<<","<<y2<<"]"<<endl;}while(y1*y2>=0);x=root(x1,x2);cout<<"在"<<x1<<"与"<<x2<<"之间,方程的解为"<<x<<endl;return 0;   }float f1(float x){    return(x*x*x-4*x*x+6*x-10);}float root(float x1,float x2){    float y1,x,y;y1=f(x1);do{    x=point(x1,x2);y=f(x);if(y*y1>0){   y1=y;x1=x;}else x2=x;}while(fabs(y)>=0.0001);    return x;}float point(float x1,float x2){    float y;    y =(x1*f(x2)-x2*f(x1))/(f(x2)-f(x1));return y;}

例十五

#include<iostream>using namespace std;float Factorial(int n);int main(){   int a;   float f;   cout<<"input an integer number:";   cin>>a;   f=Factorial(a);   cout<<a<<"!= "<<f<<endl;   return 0;}float Factorial(int n){    float fact;if(n==0)fact=1;elsefact =n*Factorial(n-1);    return fact;}

例十六

#include<iostream>using namespace std;const N=8;long fibo(int n);int main(){   long f=fibo(N);   cout<<"Fibonacci数列第8项的值为:"<<f<<endl;   return 0;}long fibo(int n){   if(n==1)return 1L;   else if(n==2)return 1L;   else   return fibo(n-1)+fibo(n-2);}

例十七

#include<iostream>using namespace std;int i;            //文件作用域int main(){   i=5;           //给文件作用域的变量i赋值   {      int i;      //块作用域  i=7;          cout<<"内层i ="<<i<<endl;  //输出7   }    cout<<"外层i ="<<i<<endl;     //输出5   return 0;}

例十八

#include<iostream>using namespace std;int i=1;                    //定义具有文件作用域的变量iint main()                  {    cout<<"i= "<<i<<endl;   //输出具有文件作用域的变量i的值1int i=5;                //定义局部变量i，此时覆盖文件作用域变量i    cout<<"i= "<<i<<endl;   //此时输出上一条语句定义的局部变量i的值5    {   int i=7;               //定义块作用域变量i，此时覆盖前面定义的两个变量i   cout<<"i= "<<i<<endl; //输出块作用域变量i的值7   cout<<"i= "<<::i<<endl; //输出文件作用域变量i的值1}cout<<"i= "<<i<<endl;cout<<"i= "<<::i<<endl;return 0;}

例十九

#include<iostream>using namespace std;int max(int x,int y){    int z;z=x>y?x:y;return z;}int main(){   extern int a,b;        //外部变量说明   cout<<max(a,b)<<endl;   return 0;}int a=13,b=-8;            //定义全局变量

例二十

#include<iostream>using namespace std;void sort(int);void echoa();int a[5] = {6,3,9,8,2};         //定义全局数组aint main(){    echoa();sort(5);echoa();    return 0;}void echoa(){    for(int i=0;i<5;i++)cout<<a[i]<<'\t';cout<<endl;}void sort(int n)                //选择排序法{    int i,j,min,temp;for(i=0;i<n-1;i++){   min=1;   for(j=i+1;j<n;j++)   if(a[j]<a[min])   min=j;   temp=a[i];a[i]=a[min];a[min]=temp;}}

例二十一

#include<iostream>using namespace std;int a=3,b=5;         //定义a,b全局变量int main(){   int a=8;          //a是局部变量   int c;   c=a>b?a:b;        //此时，a=8,b=5      cout<<c<<endl;   return 0;}

例二十二

#include<iostream>using namespace std;int f(int a){   auto int b=0;     //b为自动局部变量   static int c=3;   //c为静态局部变量   b++;   c++;   return (a+b-c);}int main(){    int a=2,i;for(i=0;i<3;i++)  //三次调用f函数   cout<<f(a)<<endl;return 0;}

例二十三

#include<iostream>using namespace std;int fun(int);int main(){    int i,k;cout<<"请输入一个非负整数:";cin>>k;for(i=1;i<=k;i++)cout<<i<<"!="<<fun(i)<<endl;return 0;}int fun(int n){    static int f=1;            //f为静态局部变量，每一次函数执行后i!的值都会保留    f=f*n;    return f;}

例二十四

#include<iostream>using namespace std;int fun(int);int main(){    int i,k;cout<<"请输入一个非负整数:";cin>>k;for(i=1;i<=k;i++)cout<<i<<"!= "<<fun(i)<<endl;return 0;}int fun(int n){    register int i,f=1;for(i=1;i<=n;i++)f=f*i;return f;}

例二十五

//文件file1.cpp#include<iostream>using namespace std;int a;                    //全局变量int power(int n);         //原型说明int main(){    int b=3,c,d,m;cout<<"enter a and m:"<<endl;cin>>a>>m;c=a*b;cout<<"a= "<<a<<"\tb= "<<b<<"\tc= "<<c<<endl;d=power(m);                                     //调用power函数，求a的m次方cout<<"a= "<<a<<"\tm= "<<b<<"\td= "<<d<<endl;return 0;}//文件file2,cppextern int a;int power(int n)                 //该函数的功能是求a的n次方{    int i,y=1;for(i=1;i<=n;ti++)y*=a;    return y;}

二.编程实现课本每一个编程习题

2.

#include<iostream>   using namespace std;  long intPower(int base,int exponent){long a=1;for(int i=1;i<=exponent;i++)a=a*base;return a;}int main(){   int base,exponent;cout<<"please input the base and exponent:"<<endl;cin>>base>>exponent;cout<<"the result is:"<<intPower(base,exponent)<<endl;return 0;}

3.

#include<iostream>   #include<iomanip>using namespace std;  int fun(int num){for(int i=2,flag=1;i<num;i++)if(num%i==0)flag=0;return flag;}int main(){int b,num;cout<<"请输入一整数"<<endl;cin>>num;b=fun(num);if(b==1) cout<<"此为素数"<<endl;if(b==0) cout<<"此非素数"<<endl;return 0;}

4.

#include<iostream>#include<iomanip>   using namespace std;int fun(int n){int i,m=n;for(i=1;;){m/=10;if(m==0) break;i*=10;}if(i==1) return n;int temp=i;int j,a[10];for(j=0;temp!=0;j++){a[j]=n/temp;n=n-a[j]*temp;temp/=10;}for(j=j-1;j>=0;j--){n+=a[j]*i;i/=10;}return n;}int main(){int num,result;cout<<"请输入一十进制正整数：";cin>>num;result=fun(num);cout<<num<<"的逆序数为："<<result<<endl;return 0;}

5.

#include<iostream>   #include<iomanip>using namespace std;  char fun(int mark){char level;if(mark>=90&&mark<=100) level='A';else if(mark>=80) level='B';else if(mark>=70) level='C';else if(mark>=60) level='D';else level='fail';return level;}int main(){int mark;cout<<"请输入成绩"<<endl;cin>>mark;cout<<"分数对应等级为:"<<fun(mark)<<endl;return 0;}

6.

#include<iostream>#include<iomanip>   using namespace std;  float average(){float a[10],sum=0,c;cout<<"please input 10 scores:"<<endl;for(int i=0;i<10;i++){cin>>a[i];sum=sum+a[i];}c=sum/10;return c;}int main(){float b;b=average();cout<<"the average is:"<<b<<endl;}

7.

#include<iostream>#include<iomanip>   using namespace std;  int fun(int n,int m){int t,r;if(m>n){t=m;m=n;n=t;}while((r=n%m)!=0){n=m;m=r;}return m;}int fun2(int n,int m){int a,b;a=fun(n,m);b=m*m/a;return b;}int main(){int x,y;cout<<"请输入两个整数："<<endl;cin>>x>>y;cout<<x<<"和"<<y<<"的最大公约数为："<<fun(x,y)<<endl<<x<<"和"<<y<<"的最小公倍数为："<<fun2(x,y)<<endl;return 0;}

8.

#include<iostream>#include<iomanip>   using namespace std;  void fun1(){for(int i=1;i<=9;i++){for(int j=1;j<=9;j++)cout<<j<<"*"<<i<<"="<<j*i<<'\t';cout<<endl;}}void fun2(){for(int i=1;i<=9;i++){for(int j=1;j<=i;j++)cout<<j<<"*"<<i<<"="<<j*i<<'\t';cout<<endl;}}void fun3(){for(int i=1;i<=9;i++){for(int j=1;j<=9;j++){if(j<i) cout<<'\t';else cout<<j<<"*"<<i<<"="<<j*i<<'\t';}cout<<endl;}}int main(){fun1();cout<<endl;fun2();cout<<endl;fun3();cout<<endl;return 0;}   

9.(1)

#include<iostream>#include<iomanip>   using namespace std;  int fun1(int a,int b,int c){int max;if(a>b&&a>c) max=a;else if(b>a&&b>c) max=b;else max=c;return max;}int fun2(int a,int b,int c){int min;if(a<b&&a<c) min=a;else if(b<a&&b<c) min=b;else min=c;    return min;}int fun3(int a,int b,int c){int aver;aver=(a+b+c)/3;return aver;}int main(){int a,b,c;cout<<"请输入三个整数:"<<endl;cin>>a>>b>>c;cout<<"最大值为："<<fun1(a,b,c)<<endl<<"最小值为："<<fun2(a,b,c)<<endl<<"平均值为："<<fun3(a,b,c)<<endl;return 0;}

（2）

#include<iostream>#include<iomanip>   using namespace std;  int fun1(int& a,int& b,int& c){int max;if(a>b&&a>c) max=a;else if(b>a&&b>c) max=b;else max=c;return max;}int fun2(int& a,int& b,int& c){int min;if(a<b&&a<c) min=a;else if(b<a&&b<c) min=b;else min=c;    return min;}int fun3(int& a,int& b,int& c){int aver;aver=(a+b+c)/3;return aver;}int main(){int a,b,c;cout<<"请输入三个整数:"<<endl;cin>>a>>b>>c;cout<<"最大值为："<<fun1(a,b,c)<<endl<<"最小值为："<<fun2(a,b,c)<<endl<<"平均值为："<<fun3(a,b,c)<<endl;return 0;}

（3）

#include<iostream>#include<iomanip>   using namespace std;int a,b,c;  int fun1(){int max;if(a>b&&a>c) max=a;else if(b>a&&b>c) max=b;else max=c;return max;}int fun2(){int min;if(a<b&&a<c) min=a;else if(b<a&&b<c) min=b;else min=c;    return min;}int fun3(){int aver;aver=(a+b+c)/3;return aver;}int main(){cout<<"请输入三个整数:"<<endl;cin>>a>>b>>c;cout<<"最大值为："<<fun1()<<endl<<"最小值为："<<fun2()<<endl<<"平均值为："<<fun3()<<endl;return 0;}