#include<iostream> using namespace std; int main() { float pi=3.14159; int s,r=4;
s=r*r*pi; cout<<s<<endl; return 0; }#include<iostream> using namespace std; int main() {
//int x; float a=15.75; double b=323.01; cout>>(int)a<<endl; cout>>(int)(b
+0.5)%10<<endl; cout>>(int)b%(int)a+1<<endl; return 0; }#include<iostream> using
namespace std; int main() { int a,b,c,d,ans; a=2;b=3;c=4; d=a-b; a=d+c; ans=a*b;
cout<<"Ans="<<ans<<endl; return 0; }#include<iostream> #include<iomanip> using namespace
std; int main() { cout<<10.0/6.0<<endl; cout<<fixed<<setprecision(8)<<10.0/6.0<<endl;
return 0; }#include<iostream> #include<iomanip> using namespace std; int main() { int a;
cin>>a; cout<<"dec:"<<dec<<a<<endl; cout<<"hex:"<<hex<<a<<endl; cout<<"oct:"<<setbase
(8)<<a<<endl; return 0; }#include<iostream> #include<cstdio> using namespace std; int
main() { int a=100; double b=246.343; printf("a=%d\n",a); printf("2*a=%d\n",2*a);
printf("a=%2d\n",a); printf("%3f\n",b); printf("%20.2lf\n",b); printf("%-20.2lf\n",b);
printf("%.2lf\n",b); return 0; } #include<iostream> using namespace std; int
a,b,c,ans=100; int main() { a=1; b=2; c=5; a=a+b; b=a+b+c; ans=ans+a+b+c;
cout<<ans<<endl; return 0; }