第二章例題
F0201.cpp
#include<iostream>
using namespace std;
void main()
{
double radius;
cout<<"input the radius:";
cin>>radius;
double result=radius*radius*3.14*4;
cout<<"the result is:"<<result<<"/n";
}
F 0204.cpp--直角三角形
#include<iostream>
void main()
{
int i,j;
for (i=1;i<=10;i++)
{for(j=1;j<=i;j++)
std::cout<<"M";
std::cout<<"/n";
}
}
f0205--倒三角形
#include<iostream>
void main()
{
int i,j;
for (i=1;i<=11;i++)
{ for(j=1;j<=11;j=j+1)
if(j<i)
std::cout<<" ";
else if(12-j<i)
std::cout<<" ";
else std::cout<<"M";
std::cout<<"/n";
}
}
或者、
void main()
{
int i,j;
for (i=1;i<=11;++i)
{ for(j=1;j<=i-1;++j)
std::cout<<" ";
for (int k=1;k<=21-2*i;++k)
std::cout<<"M";
std::cout<<"/n";
}
}
F0206--順序英文字母三角形
#include<iostream>
void main()
{
int i,j,l;
for (i=1;i<=11;i++)
{
l=97;
for(j=1;j<=i-1;j++)
std::cout<<" ";
for (int k=1;k<=21-2*i;k++, l++)
std::cout<<char(l);
std::cout<<"/n";
}
}
f0207判斷素數--使用子函數
#include<iostream>
int isprime(int n)
{ int i;
for(i=2;i<n/2;i++)
{
if(n%i==0)
{ std::cout<<"is not a prime/n";
return 1;}
}
std::cout<<"is a prime/n";
return 1;
}
void main()
{ int n;
std::cout<<"input a number:/n";
std::cin>>n;
std::cout<<isprime(n);
};
不使用子函數
#include<iostream>
int main()
{ int n,i;
std::cout<<"input a number:/n";
std::cin>>n;
for(i=2;i<n/2;i++)
if(n%i==0)
{ std::cout<<"is not a prime/n";
return 1;
}
std::cout<<"is a prime/n";
};
優化一下。。。。。
#include<iostream>
#include<cmath>
using namespace std;
int main()
{
cout<<"please input a number :/n";
int m;
cin>>m;
double sqrtm=sqrt(m*1.0);
for (int i=2;i<=sqrtm;i++)
if (m%i==0)
{
cout<<m<<" isn't a prime./n";
return 1;
}
cout<<m<<"is a prime";
}
百錢買百雞
#include<iostream>
using namespace std;
void main()
{
for (int cock=1;cock<=13;cock++)
for(int hen=1;hen<=18;hen++)
if ((100-cock-hen)%3==0 && 7*cock+5*hen+(100-cock-hen)/3==100)
cout<<"cock:"<<cock<<", hen:"<<hen<<",chick"<<100-cock-hen<<endl;
}
求Pi 執行結果 乖乖的
#include<iostream>
#include<cmath>
using namespace std;
int main()
{
double sum=0,item=1;
long demon=-1;
int sign=-1;
do{
demon+=2;
sign*=-1;
item=sign*1.0/demon;
sum+=item;
} while(abs(item)>1e-6);
cout<<"Pi="<<fixed<<sum*4<<endl;
}
這個有點問題貌似。。在哪裏呢??