c++实验一

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实验结论

 2-28  if...else:

#include<iostream>

using namespace std;

int main()

{char ch;

cout<<"Menu：A(dd)、D(delete)、S(ort)、Q(uit)，Select one："<<endl;

cout<<"A表示增加，D表示删除，S表示排序，Q表示退出!"<<endl;

cout<<"Enter ch: ";
cin>>ch;
while(ch!='Q')
{
if(ch=='A')
{
cout<<"数据已经增加!"<<endl;
cout<<"Enter ch: ";
cin>>ch;continue;
}
else
if(ch=='D')
{
cout<<"数据已经删除!"<<endl;
cout<<"Enter ch: ";
cin>>ch;continue;
}
else
if(ch=='S')
{
cout<<"数据已经排序!"<<endl;
cout<<"Enter ch: ";
cin>>ch;continue;
}
else
{
cout<<"错误!"<<endl;
cout<<"请从新输入："<<endl;
cout<<"Enter ch: ";
cin>>ch;
}
}
if(ch=='Q')
cout<<"程序结束!"<<endl;
}

   

switch:

#include <iostream>
using namespace std;
int main()
{char n;

cout<<"Menu: A(dd) D(elete) S(ort) Q(uit),Select one: "<<endl;

cin>>n;
while(n!='Q')
{switch(n)
{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;
}}
cin>>n;
}
return 0;
}

 

2-29 while

#include <iostream>

using namespace std;

int main () {

int i,j,n,m;i=2;

while(i<101){

m=1,n=i/2;j=2;

while(j<=n){

if(i%j==0)
{
m=0;
break;
}
j++;
}
if(m)
cout<<i<<" ";
i++;
}
}

do...while

#include<iostream>
int main()
{
int i,j,n,m;
i=2;
do
{
m=1;
n=i/2;
j=2;
do
{
if(i%j==0)
{
m=0;
break;
}
j++;
}
while(j<=n);
if(m)
cout<<i<<" ";
i++;
}
while(i<101);
}

 for:

# include<iostream.h>
void main()
{
inti,j,n,m;
for(i=2;i<101;i++)
{
m=1;
n=i/2;
for(j=2;j<=n;j++)
{
if(i%j==0)
{
m=0;
break;
}
}
if(m)
cout<<i<<" ";
}
}

 

2-32

while:

#include <iostream>
#include <stdlib.h>
#include <time.h>
using namespace std;
int main()
{
int x;
srand(time(0));
int number=rand()%100+1;
cout<<"猜一下这个数: ";
cin>>x;
while(1)
{
if(x!=number)
{
if(x<number)
{
cout<<"小了"<<endl;
}
else
{
cout<<"大了"<<endl;
}
}
else
{
cout<<"恭喜猜对了！"<<endl;break;
}
cin>>x;
}
return 0;
}

do...while:

#include <iostream>
#include <stdlib.h>
#include <time.h>
using namespace std;
int main()
{
int x;
srand(time(0));
int number=rand()%100+1;
cout<<"猜一下这个数: "<<endl;
cin>>x;
do
{
if(x!=number)
{
if(x<number)
{
cout<<"小了"<<endl;
}
else
{
cout<<"大了"<<endl;
}
}
else
{
cout<<"恭喜猜对了！"<<endl;break;
}
cin>>x;
}while(1);
return 0;
}

2-34

#include<iostream>

#include<iomanip>

using namespace std;

int main()
{
enum color{red,yellow,blue,white,black};

color pri;

int i,j,k,n=0,loop;

for(i=red;i<=black;i++)
{
for(j=red;j<=black;j++)
{
if(i!=j)
{
for(k=red;k<=black;k++)
{
if(k!=i&&k!=j)
{
n=n+1;

cout<<setw(3)<<n;

for(loop=1;loop<=3;loop++)
{
switch(loop)
{
case 1:pri=color(i);break;

case 2:pri=color(j);break;

case 3:pri=color(k);break;

default :break;
}

switch(pri)
{
case red:cout<<setw(8)<<"red";break;

case yellow:cout<<setw(8)<<"yellow";break;

case blue:cout<<setw(8)<<"blue";break;

case white:cout<<setw(8)<<"white";break;

case black:cout<<setw(8)<<"black";break;

default :break;
}
}

cout<<endl;
}
}
}
}
}

cout<<"total:"<<n<<endl;

return 0;
}

实验总结与体会

 要注意c与c++语言的区别；while和do...while语句要注意再循环体中要包含改变循环条件表达式值的语句；break使程序从循环体中跳出，continue结束本次循环。

 

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