第七周作业

5.1

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

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;
}

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;
}

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;
}

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;
}

5.6

#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 numbers:";
cin>>a>>b;
c=max(a,b);
cout<<"a="<<a<<"b="<<endl;
cout<<"max is"<<c<<endl;
return 0;
}

5.7

#include<iostream>
using namespace std;
int spr(int x)
{
x=x*x;
return x;
}
int main()
{
int t=10;
int s=spr(t);
cout<<"t="<<t<<endl
<<"spr("<<t<<")="<<s<<endl;
return 0;
}

书上例题过于繁多，也就不一一打上。

下面是书上练习题

1.说明程序的执行过程和运算结果

#include<iostream>
#include<cmath>
using namespace std;
double squ(double x);
int main()
{
double x;
cout<<"please input x:";
cin>>x;
cout<<"the spuare root of"<<x<<"is"<<squ(x)<<endl;
return 0;
}
double squ(double x)
{
double s1,s2;
s1=0.5*(1.0+x);
do{
s2=s1;
s1=(s2+x/s2)*0.5;
}while(fabs(s2-s1)>1.0E-6);
return s1;
}

2.求整数次幂的函数

#include<iostream>
using namespace std;
long intpower(int base,int exponent);
int main()
{
long n;
int base,exponent;
cout<<"请输入基数及其幂:";
cin>>base>>exponent;
n=intpower(base,exponent);
cout<<base<<"的"<<exponent<<"次幂是"<<n<<endl;
return 0;
}
long intpower(int base,int exponent)
{
long result=1;
int i;
if(exponent!=0)
for(i=1;i<=exponent;i++)
result*=base;
return result;
}

5.编写一个函数，按照所给的百分制分数，返回与该分数对应的等级代号字符。

#include<iostream>
using namespace std;
char grade(int);
int main()
{
int score;
cout<<"请输入百分制成绩（1~100）:";
cin>>score;
char ch=grade(score);
cout<<score<<"对应的等级为:"<<ch<<endl;
return 0;
}
char grade(int n)
{
char ch;
if(n>=90&&n<=100)ch='A';
else if(n>=80)ch='B';
else if(n>=70)ch='C';
else if(n>=60)ch='D';
else ch='E';
return ch;
}

6.编写一个函数，内放10个学生成绩，求平均成绩。

#include<iostream>
using namespace std;
char grade(int);
int main()
{
int score;
cout<<"请输入10个学生的成绩："<<endl;
cin>>score;
char ch=grade(score);
return 0;
}
char grade(int)
{
int sum=0,score;
sum+=score;
score++;
cout<<"这10个学生的成绩平均值为："<<sum/10<<endl;
return 0;
}