作业1

2-28

include

using namespace std;
int main()
{
char x;
cout<<"Menu:A(dd)D(elete)S(ort)Q(uit),Select one:";
cin>>x;
switch(x)
{
case 'A':
cout<<"数据已经增加";break;
case 'D':
cout<<"数据已经删除";break;
case 'S':
cout<<"数据已经排序";break;
case 'Q':
break;
}
return 0;
}

2-29

include

using namespace std;
int main()
{
int i,j,n=1,a[100];
a[0]=2;
for(i=3;i<=100;i++)
{
for(j=2;j<i;j++)
if(i%j==0)
break;
if(j>=i)
{
a[n]=i;
n++;
}
}
for(i=0;i<n;i++)
cout<<a[i]<<' ';
return 0;
}

2-29

include

using namespace std;
int main()
{
int i=3,j=2,n=1,a[100];
a[0]=2;
do{
j=2;

    while(j<i)
    {
        if(i%j==0)
           break;
           j++;
    }
        if(j>=i)
    {
            a[n]=i;
            n++;
    }
    i++;
    if(i>100)
        break;
}while(i);
for(i=0;i<n;i++)
cout<<a[i]<<' ';
return 0;

}

2-29

include

using namespace std;
int main()
{
int i=3,j=2,n=1,a[100];
a[0]=2;
while(i)
{
j=2;
while(j<i)
{
if(i%j==0)
break;
j++;
}
if(j>=i)
{
a[n]=i;
n++;
}
i++;
if(i>100)
break;
}
for(i=0;i<n;i++)
cout<<a[i]<<' ';
return 0;
}

2-32

include

using namespace std;
int main()
{
int i,x;
cin>>i;
do{
if(x>i)
{cout<<"猜大了请继续";continue;}
else if(x<i)
{cout<<"猜小了请继续";continue;}
else
cout<<"猜对了!";break;
}while(cin>>x);
return 0;
}

2-32

include

using namespace std;
int main()
{
int i,x;
cin>>i;
while(cin>>x)
{
if(x>i)
{cout<<"猜大了请继续";continue;}
else if(x<i)
{cout<<"猜小了请继续";continue;}
else
cout<<"猜对了!";break;
}
return 0;
}

2-34
///思路：该问题是一个简单的排列组合的问题，需要用到阶乘以及阶乘的乘除问题，因此想到需要用到递归+嵌套使用

include

using namespace std;
double fun1(int x)
{
double f;
if(x==0)
f=1;
else
f=fun1(x-1)x;
return f;
}
double fun2(int a,int b,int c)
{
double result;
result=fun1(a)/(fun1(b)fun1(c));
return result;
}
int main()
{
double n,k,all,z;
cout<<"Please entre n and k:";
cin>>n>>k;
z=n-k;
all=fun2(n,k,z);
cout<<all;
return 0;
}