The setprecision is used to control the digits of an output stream of a floating point value

#include<iostream.h>
#include<iomanip.h>
void main()
{
float a,b,c;
a=5;b=3;c=a/b;
cout<<setprecision(1)<<c<<endl;
cout<<setprecision(2)<<c<<endl;
cout<<setprecision(3)<<c<<endl;
cout<<setprecision(4)<<c<<endl;
cout<<setprecision(5)<<c<<endl;
cout<<setprecision(6)<<c<<endl;
}

Output:
1.7
1.67
1.667
1.6667
1.66667
1.666667