C++控制输出保留小数点数setprecision

#include<iostream> #include<iomanip> using namespace std; int main() { double a=0.123456789111; cout<<a<<endl; cout<<setprecision(1)<<a<<endl; cout<<setprecision(2)<<a<<endl; cout<<setprecision(3)<<a<<endl;//显然是去尾 }