c++课后题答案钱能第二版

1、1-1#include<iostream>using namespace std; void main()cout<<"I'm a student"<<endl;1-2#include<iostream>using namespace std;int i,j;void main()for(i=1;i<=4;i+)for(j=1;j<=4-i;j+)cout<<" "for(j=1;j<=2*i-1;j+)cout<<"*"cout<

2、<endl<<endl;for(i=1;i<=3;i+)for(j=1;j<=i;j+)cout<<" "for(j=1;j<=(7-2*i);j+)cout<<"*"cout<<endl<<endl;2-13#include<iostream>using namespace std;int i,j;void main()for(i=1;i<=9;i+)cout<<i<<"t"for(i=1;i<=9;i

3、+)cout<<"-"<<"t"cout<<endl<<endl;for(i=1;i<=9;i+) /下三角形式for(j=1;j<=i;j+)/cout<<i*j<<"t"/cout<<endl;cout<<endl<<endl; for(i=1;i<=9;i+) /shang三角形式cout<<"t"<<i;for(i=0;i<9;i+)cout<&l

4、t;"t"<<"-"cout<<endl<<endl;for (i=1;i<=9;i+) for(j=1;j<=i;j+)cout<<"t"for(j=i;j<=9;j+)/cout<<i*j<<"t"/cout<<endl;3-3#include<iostream>#include<vector>#include<cmath> using namespace std; void

5、 main() int a11=6,3,7,1,4,8,2,9,11,5;vector<int> ve(a,a+10);int he=0;int sum=0;float average;float s;for(int i=0;i<ve.size();i+)sum+=vei;average=sum/ve.size();for( i=0;i<ve.size();i+)he+=(vei-average)*(vei-average);s=sqrt(he/ve.size();cout<<"s="<<s<<endl;4-6#i

6、nclude<iostream>#include<fstream>#include<sstream>using namespace std;void main() int a=0; ifstream in("D:aaa.txt"); for(string s;getline(in,s);) for(istringstream sin(s);sin>>a;) if(a%3=0)&&(a%5=0)&&(a%7=0) cout<<a<<"能同时被3 5 7整除&quo

7、t;<<endl; else if(a%3=0)&&(a%5)&&(a%7) cout<<a<<"能被3整除 不能被5整除 也不能被7整除"<<endl; else if(a%3)&&(a%5=0)&&(a%7) cout<<a<<"能被5整除 不能被3整除 也不能被7整除"<<endl; else if(a%3)&&(a%5)&&(a%7=0) cout<<a&l

8、t;<"能被7整除 不能被3整除 也不能被5整除"<<endl; else if(a%3)&&(a%5)&&(a%7) cout<<a<<"不能被3 5 7 任意一个整除"<<endl; 4-8#include<iostream>using namespace std;void transform(int );int n;void main() /十进制数转换为二进制数cout<<"输入要转换的十进制整数："<<e

9、ndl;int num;cin>>num;transform(num); void transform(int n)if (n<2)cout<<n;else if(n>=2)transform(n/2);cout<<n%2; 5-5#include<iostream>#include<fstream>#include<sstream>#include<vector>#include<algorithm>using namespace std;typedef vector<vecto

10、r<int> > vii;/-vector<int> read()vector<int>a;ifstream in("D:aaa.txt");for(string s;getline(in,s);) int c; for(istringstream sin(s);sin>>c;) a.push_back (c);if(a.empty()cout<<"NO ELement!"<<endl;elsecout<<"从磁盘中读取数据输出结果是："<

11、<endl;for(int i=0;i<a.size();i+) cout<<ai<<" " /输出读取的数据 cout<<endl<<endl; return a; /- int bit_twice_sum(int a) int sum=0; for(int x=a;x;x/=10)sum+=(x%10)*(x%10); return sum; /- bool compare(int sum1,int sum2) return bit_twice_sum(sum1)<bit_twice_sum(sum2);

12、 /- void insert_cout(vector<int>ve) cout<<"请输入你想插入的数："<<endl; int num; cin>>num; ve.push_back(num); sort(ve.begin(),ve.end(),compare); cout<<endl<<"插入数之后，再按各位数字平方之和的大小输出："<<endl; for(int i=0;i<ve.size();i+) cout<<vei<<"

13、; " cout<<endl; /-void main() vector<int>v0=read(); sort(v0.begin(),v0.end(),compare); cout<<endl<<"按各位数字平方之和的大小输出："<<endl; for(int i=0;i<v0.size();i+) cout<<v0i<<" " cout<<endl; insert_cout(v0); /-8-1#include<iostream>

14、;#include<cmath>using namespace std;/-class Pointprotected:double x,y; /x y 轴分量public:void set(double ix,double iy)/设置坐标x=ix;y=iy;/-double xoffset()/取y轴坐标分量return x;/-double yoffset()/取x轴坐标分量return y;/-double angle()/取点的极坐标return (180/3.14159)*atan2(y,x);/-double radius()/取点的极坐标半径return sqrt(x

15、*x+y*y);void Point: add()x+=5;y+=6;cout<<"x="<<x<<endl<<"y="<<y<<endl;void main()Point p;double x,y;cout<<"Enter x and y:"<<endl;cin>>x>>y;p.set(x,y);cout<<"angle="<<p.angle()<<endl&

16、lt;<"radius="<<p.radius<<endl<<"x offset="<<p.xoffset()<<endl<<"y offset="<<p.yoffset()<<endl;p.add();8-3#include<iostream>#include<iomanip>using namespace std;class Dateprivate:int year,month,day;public:voi

17、d set(int d,int m,int y);void add();void print();void Date:set(int d,int m,int y)year=y;month=m;day=d;void Date:add()day=day+1;/cout<<"加一天之后日期是："<<day<<endl;void Date:print()cout<<setfill('0');cout<<setw(2)<<day<<'/'<<setw(2)&

18、lt;<month<<'/'<<setw(4)<<year<<endl;/cout<<setfill(' ');void main()Date d1,d2;d1.set(10,4,2012);d1.print();d2.set(10,4,2012);d2.add();d2.print();8-4/*多文件结构*/Time.cpp#include"Time.h" void Time:set(int h,int m,int s)hour=h;minite=m;second=s;vo

19、id Time:print()setfill('0');cout<<setw(2)<<hour<<':'<<setw(2)<<minite<<':'<<setw(2)<<second<<endl;#include"Time.h"/主函数void main()Time t;t.set(14,47,39);t.print();9-1#include<iostream>using namespace std;cla

20、ss MyClassint number;public:MyClass();MyClass(int);MyClass();void Display();/-MyClass:MyClass()cout<<"Constructing normally.n"/-MyClass:MyClass(int m):number(m)cout<<"Constructing with a number:"<<number<<endl;/-void MyClass:Display()cout<<"Display s number:"<<number<<endl;/-MyClass :MyClass()cout<<"Destructing.n"/-void main()MyClass obj1;MyClass obj2(20);obj1.Display();obj2.Display();/-9-3#include<iostream>using namespace std;/-class CATint *itsAge;public:CAT():itsAge(new i