#include using namespace std; int main() { cout<<"**"<<endl; cout<<" 小小计算器 "<<endl; cout<<" 1.加法 "<<endl; cout<<" 2.减法 "<<endl; cout<<" 3.乘法 "<<endl; cout<<" 4.除法 "<<endl; cout<<" 5.圆的面积 "<<endl; cout<<" 6.字母的大小写转换 "<<endl; cout<<" 7.列出所有奇数 "<<endl; cout<<" 8.求所有奇数的和 "<<endl; cout<<""<<endl; cout<<"请输入三个数,进行1到5的运算，每个数以空格结束"<<endl; int a,b,add,sub,mul,div,r; double s; cin>>a>>b>>r; const PI=3.14; add=a+b; sub=a-b; mul=ab; div=a/b; s=PIr*r; cout<<"加:"<<add<<endl; cout<<"减:"<<sub<<endl; cout<<"乘:"<<mul<<endl; cout<<"除:"<<div<<endl; cout<<"面积:"<<s<<endl; cout<<endl; cout<<"请输入字母，可进行大小写转换"<<endl; char ch; cin>>ch; if (ch>=65&&ch<=90) { ch=ch+32; cout<<ch<<endl; } else if(ch>=97&&ch<=122) { ch=ch-32; cout<<ch<<endl; } else cout<<"输入非法"<<endl; cout<<endl; cout<<"请输入两个数比较他们的大小，每个数以空格结束"<<endl; float num1,num2; cin>>num1>>num2; if (num1>=num2) cout<<num1<<endl; else cout<<num2<<endl; cout<<endl; cout<<"循环一：请输入一个二百以内的整数，可找出从零到该数中的所有奇数，并求和"<<endl; int t=0,num3; cin>>num3; for (int i=1;i<=num3;i+=2) { cout<<i<<" "; t+=i; } cout<<endl; cout<<"求和结果："<<t<<endl; cout<<endl; cout<<"循环二：请输入一个二百以内的整数，可找出从零到该数中的所有奇数，并求和"<<endl; int j=1,k=0; while (j<=num3) { cout<<j<<" "; k+=j; j+=2;
}
cout<<endl;
cout<<"求和结果："<<k<<endl;
cout<<endl;
cout<<"循环三：请输入一个二百以内的整数，可找出从零到该数中的所有奇数，并求和"<<endl;
{
int l=1,m=0;
do
{
cout<<l<<" ";
m+=l;
l+=2;
}while (l<=num3);
cout<<endl;
cout<<"求和结果："<<m<<endl;
}
return 0;
}