how can i output numbers of only 4 decimal places in C++ code example

Example 1: how print fload wiht 3 decimal in c++

#include <iostream>
#include <cstdio>
using namespace std;

int main() 
{
    // This code helps you to print a number with desired decimal
    double Number=10.3454;
    printf("%.3lf",Number);

    return 0;
}

Example 2: how to format decimal palces in c++

std::cout << std::setprecision(2) << std::fixed;
// where the 2 is how many decimal places you want
// note you need to <iomanip>