第七周作业

例5.1

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

例5.2

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

例5.3

#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5.4

#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5.5

#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5.6

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

例5.7

#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5.8

#include<iostream>using namespace std;void swap(int u,int v);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; temp=u; u=v;

例5.10

#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5.13

#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5.14

#include<iostream>#include<cmath>using namespace std;float f(float x);                            //求函数值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                             //输入x1,x2,直到f(x1)与f(x2)异号 {  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);          //求(x1,x2)区间的根 cout<<"在"<<x1<<"与"<<"之间，方程的解为"<<x<<endl;      return 0;} float f(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5.16

#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;elsereturn fibo(n-1)+fibo(n-2);}

例5.18

#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icout<<"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俩个变量icout<<"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;                 //输出局部变量i的值5cout<<"i="<<::i<<endl;                //输出文件作用域变量i的值1return 0；}

例5.19

#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;                  //全部变量定义

例5.20

#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)           //选择法排序{int i,j,min,temp;for(i=0;i<n-1;i++){min=i;for(j=i+i;j<n;j++){min=i;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5.21

#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=5cout<<c<<endl;return 0;}

例5.22

#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5.23

#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;}