实验结论ios
P63 2-28c++
（1）If..else.. 进行判断，break continue控制程序流程函数
#include<iostream>ui
using namespace std;spa
int main(){3d
char choice;blog
while(1){ci
cout<<"Menu:A(dd) D(elete) S(ort) Q(uit),Select one:";it
cin>>choice;io
if(choice=='A'||choice=='a') cout<<"Dates have been added"<<endl;
else if(choice=='D'||choice=='d') cout<<"Dates have been deleted"<<endl;
else if(choice=='S'||choice=='s') cout<<"Dates have been sorted"<<endl;
else if(choice=='Q'||choice=='q') break;
else cout<<"no such choice"<<endl;
}
return 0;
}
（2）switch循环语句
#include<iostream>
#include<cstdlib>
using namespace std;
int main(){
char choice;
while(1){
cout<<"Menu:A(dd) D(elete) S(ort) Q(uit),Select one:";
cin>>choice;
switch(choice){
case 'A':
cout<<"Dates have been added"<<endl;
break;
case 'D':
cout<<"Dates have been deleted"<<endl;
break;
case 'S':
cout<<"Dates have been sorted"<<endl;
break;
case 'Q': exit(0);
default: cout<<"no such choice"<<endl; break;
}
}
return 0;
}
P63 2-291穷举法找质数
（1）for循环
#include<iostream>
#include<cmath>
using namespace std;
int main(){
int i,m,n,t=1;
for(i=1;i<=100;i++)
{
t=1;
if(i==1) continue;//将1单独分离，不知道是否有通法。
else if(i==2)
cout<<i<<" ";
else
{
m=sqrt(i);
for(n=2;n<=m;n++)
{
if(i%n==0) t=0;
}
if(t==1) cout<<i<<" ";
}
}
return 0;
}
（2）do..while 循环
#include<iostream>
#include<cmath>
using namespace std;
int main(){
int a=1,m,i;
bool t; //尝试使用了布尔型，虽然不必。
do{
i=2;
m=sqrt(a);
if(a==1) {
t=false;
}
else
{
do{
if(a%i==0)
{
t=false;
break;
}
i++;
}while(i<=m);
if(i>m) t=true;
}
if(t==true)
cout<<a<<" ";
a++;
}while(a<=100);
return 0;
}
（3）while循环
#include<iostream>
#include<cmath>
using namespace std;
int main(){
int i,a=1,m;
while(a<=100)
{
i=2;
if(a==1) {a++;continue;}
m=sqrt(a);
while(i<=m)
{
if(a%i==0) break;
i++;
}
if(i>m) cout<<a<<" ";
a++;
}
return 0;
}
P63 2-32
（1）数字固定
#include<iostream>
using namespace std;
int main(){
int i,n;
n=40;
cout<<"Please guess the number(1~100)"<<endl;
while(1) //同窗介绍的屡次输入的方式，还有其余方法吗？
{
cin>>i;
if(i>40&&i<=100) cout<<"bigger than the number"<<endl;
else if(i<40&&i>=0) cout<<"lower than the number"<<endl;
else if(i==n) break;
else cout<<"out of range"<<endl;
}
cout<<"gradulation!you are right!"<<endl;
return 0;
}
（2）数字随机
#include<iostream>
#include<ctime>
using namespace std;
int main()
{
int rnum,i;
srand(time(NULL)); //尝试使用了随机种子。
rnum=rand()%(100)+1;
while(1)
{
cin>>i;
if(i>rnum&&i<=100) cout<<"bigger than the number"<<endl;
else if(i<rnum&&i>=0) cout<<"lower than the number"<<endl;
else if(i==rnum) break;
else cout<<"out of range"<<endl;
}
cout<<"gradulation!you are right!"<<endl;
return 0;
}
组合数
P63 2-34
#include<iostream>
using namespace std;
int comp(int n,int k) //组合数函数
{
if(k>n) return 0;
else if(k==n||k==0) return 1;
else return (comp(n-1,k-1)+comp(n-1,k));
}
int main(){
int n,k,num;
cin>>n>>k;
num=comp(n,k);
cout<<num<<endl;
return 0;
}
实验总结与体会
1.常用for循环致使do..while..和while两种循环不是很熟练。
2srand的随机种子十分有趣，对抽取随机编号程序十分有效。
3对程序排版仍是不是很熟练，有的时候会显得很乱。
4c++的代码形式相对于c十分的简练有效，特别是函数的时候，能系统自主选择最合适的方案这个设定颇有趣