c++实验一

2-28：

（1）

#include<iostream>
using namespace std;
int main(){
char c;
cout<<"Menu: A(dd) D(elete) S(ort) Q(uit),Select one:"<<endl;
do{
cin>>c;
if(c=='A'){cout<<"数据已经增加!"<<endl;continue;}
if(c=='D'){cout<<"数据已经删除!"<<endl;continue;}
if(c=='S'){cout<<"数据已经排序!"<<endl;continue;}
else break;
}while(c!='Q');
return 0;
}

（2）

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

截图：

2-29:

（1）while

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

（2）do……while

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

（3）for

#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<<" ";
}
return 0;
}

截图：

2-32：

（1）while

#include<cstdlib>
#include<ctime>
#include<iostream>
using namespace std;
int main(){
srand((unsigned)time(NULL));
int t=rand()%100;
int num,flag=0;
cout<<"请输入你猜的数字"<<endl;
cin>>num;
while(num!=t){
if(flag)
cin>>num;
if(num>t)cout<<"大了"<<endl;
else if(num<t)cout<<"小了"<<endl;
flag=1;
};
cout<<"恭喜猜对了";
}

（2）do……while

#include<cstdlib>
#include<ctime>
#include<iostream>
using namespace std;
int main(){
srand((unsigned)time(NULL));
int t=rand()%100;
int num;
cout<<"请输入你猜的数字"<<endl;
do{
cin>>num;
if(num>t)cout<<"大了"<<endl;
else if(num<t)cout<<"小了"<<endl;
}while(num!=t);
cout<<"恭喜猜对了";
}

截图：

2-34：

#include<iostream>
using namespace std;
int main(){
enum ball {red,yellow,blue,white,black};
int choice=0;
int i,j,k;
for(i=red;i<=black;i++){
for(j=red;j<=black;j++){
if(i!=j)
for(k=red;k<=black;k++){
if(i!=k&&j!=k){
switch(i){
case red:cout<<"red"<<" ";break;
case yellow:cout<<"yellow"<<" ";break;
case blue:cout<<"blue"<<" ";break;
case white:cout<<"white"<<" ";break;
case black:cout<<"black"<<" ";break;
}
switch(j){
case red:cout<<"red"<<" ";break;
case yellow:cout<<"yellow"<<" ";break;
case blue:cout<<"blue"<<" ";break;
case white:cout<<"white"<<" ";break;
case black:cout<<"black"<<" ";break;
}
switch(k){
case red:cout<<"red"<<" ";break;
case yellow:cout<<"yellow"<<" ";break;
case blue:cout<<"blue"<<" ";break;
case white:cout<<"white"<<" ";break;
case black:cout<<"black"<<" ";break;
}
cout<<endl;
choice++;
}

}
}
}
cout<<"一共有"<<choice<<"种取法";
return 0;
}