第四章作业

# include<iostream>
using namespace std;
int main()
{
int a[10];
int i;
for(i=0;i<10;i++)
a[i]=i*2+2;
for(i=0;i<10;i++)
{
cout<<a[i]<<'\t';
if((i+1)%5==0)
cout<<endl;
}
return 0;
}

# include<iostream>
using namespace std;
int main()
{
int i,math[40],n;
float aver=0.0;
int unpassedcount=0;
int highscorecount=0;
cout<<"请输入学生人数:";
cin>>n;
cout<<"请输入成绩:";
for(i=0;i<n;i++)
{
cin>>math[i];
aver+=math[i];
}
aver/=n;
for(i=0;i<n;i++)
{
if(math[i]<60) unpassedcount++;
if(math[i]>=90) highscorecount++;
}
cout<<"平均数为:"<<aver<<endl;
cout<<"90分以上人数为:"<<highscorecount<<endl;
cout<<"不及格人数为:"<<unpassedcount<<endl;
return 0;
}

# include<iostream>
using namespace std;
int main()
{
int a[10],i,big;
cout<<"please input 10 numbers:\n";
for(i=0;i<10;i++)
cin>>a[i];
cout<<"the numbers are:";
for(i=0;i<10;i++)
cout<<endl;
big=a[0];
for(i=1;i<10;i++)
if(a[i]>big)
big=a[i];
cout<<"the big number is:"<<big<<endl;
return 0;
}

# include<iostream>
# include<iomanip>
using namespace std;
int main()
{
int a[10];
int i,j,t;
cout<<"please input 10 numbers:\n";
for(i=0;i<10;i++)
cin>>a[i];
cout<<"the numbers are:";
for(i=0;i<10;i++)
cout<<setw(4)<<a[i];
cout<<endl;
for(i=0;i<9;i++)
for(j=0;j<9-i;j++)
if(a[j]>a[j+1])
{t=a[j];a[j]=a[j+1];a[j+1]=t;}
cout<<"the sorted numbers are:";
for(i=0;i<10;i++)
cout<<setw(4)<<a[i];
cout<<endl;
return 0;
}

# include<iostream>
# include<iomanip>
using namespace std;
int main()
{
int i;
int f[40]={1,1};
for(i=2;i<40;i++)
f[i]=f[i-2]+f[i-1];
for(i=1;i<40;i++)
{
if(i%4==0)
cout<<endl;
cout<<setw(12)<<f[i];
}
cout<<endl;
return 0;
}

# include<iostream>
# include<iomanip>
using namespace std;
int main()
{
int i;
int j;
int a[5][5];
for(i=0;i<5;i++)
for(j=0;j<5;j++)
if(i%2==0)
a[i][j]=i*5+j+1;
else
a[i][4-j]=i*5+j+1;
for(i=0;i<5;i++)
{
for(j=0;j<5;j++)
cout<<setw(4)<<a[i][j];
cout<<endl;
}
return 0;
}

# include<iostream>
using namespace std;
int main()
{
char str[50];
cout<<"please input strings:";
cin.get(str,50);
cout<<"the string is:";
cout<<str<<endl;
return 0;
}