实验1

2-28

if-else语句

#include <iostream>
using namespace std;
int main() 
{
    char x;
    cout<<"Menu: A(dd) D(elete) S(ort) Q(uit),Select one: "<<endl;
    cin>>x;
    while(x!='Q')
    {
        if(x=='A')
        {
            cout<<"Data has added!"<<endl;
            cout<<"Menu: A(dd) D(elete) S(ort) Q(uit),Select one:";
            cin>>x;continue;
        }
        else
        if(x=='D')
        {
            cout<<"Data has deleted!"<<endl;
            cout<<"Menu: A(dd) D(elete) S(ort) Q(uit),Select one:";
            cin>>x;continue;
        }
        else
        if(x=='S')
        {
            cout<<"Data has sorted!"<<endl;
            cout<<"Menu: A(dd) D(elete) S(ort) Q(uit),Select one:";
            cin>>x;continue;
        }
        else
        {
            cout<<"Error!"<<endl;
            cout<<"Please select again!"<<endl;
            cout<<"Menu: A(dd) D(elete) S(ort) Q(uit),Select one:";
            cin>>x; 
        }
        if(x=='Q')
    break;
}
return 0;
}

switch语句

 

#include<iostream>
using namespace std;
int main()
{
char select;
int x=1;
cout<<"Menu:A(dd) D(elete) S(ort) Q(uit),Select one:"<<endl;
while(x)
{
    cin>>select;    
    switch(select){
    case 'A':cout<<"Data has added!"<<endl;continue;
    case 'D':cout<<"Data has deleted!"<<endl;continue;
    case 'S':cout<<"Data has sorted!"<<endl;continue;
    case 'Q':i=0;break;
    default:cout<<"Error!"<<endl;
            cout<<"Please select again!"<<endl;
            cout<<"Menu: A(dd) D(elete) S(ort) Q(uit),Select one:";
}
}
return 0;
}

 2-29

while语句

#include<iostream>
using namespace std;
int main()
{
int i=1,j;
while(i<=100)
{
for(j=2;j<i;j++){
if(i%j==0)break;
}
if(i==j)
cout<<i<<" ";
i++ ;
}
}

do while语句

#include<iostream>
using namespace std;
int main()
{
  int i=1,j;
do{
for(j=2;j<i;j++)
{if(i%j==0)
break;
}
if(i==j)
cout<<i<<" ";
i++    ;
}while(i<=100);
}

for语句

#include<iostream>
using namespace std;
int main()
{
int i,j;
for(i=1;i<=100;i++){
for(j=2;j<i;j++){
if(i%j==0)
break;
}
if(i==j)
cout<<i<<" ";    
}
}

2-32

while语句

#include<iostream>
using namespace std;
int main() {
int i=88;
int j;
while(1){
cout<<"猜一个数（范围1-100）"<<endl;
cin>>j;
if(j<i)
cout<<"猜小了！"<<endl;
else if(j>i)
cout<<"猜大了！"<<endl;
else
{
cout<<"猜对了！"<<endl;
break;}
}
return 0;
}

do while语句

#include<iostream>
using namespace std;
int main() {
int i=88;
int j;
do{
cout<<"猜一个数(范围1-100)"<<endl;
cin>>j;
if(j<i)
cout<<"猜小了"<<endl;
else if(j>i)
cout<<"猜大了"<<endl;
else 
{
cout<<"猜对了！"<<endl; 
break;}    
}while(1);
return 0;
}

2-34

#include <iostream>
using namespace std;
int main()
{
    int i,j,k,x=0;
    for(i=1;i<=5;i++)
     for(j=i+1;j<=5;j++)
      for(k=j+1;k<=5;k++)
             x++;
              cout<<"5个球的取法有"<<x<<"种"<<endl;
     return 0;
}