How to retain two decimal places in c++ output

In C, use the `std::fixed` and `std::setprecision` functions (defined in the `` header file) to preserve two decimal places in the output. `std::fixed` sets the output format to a fixed decimal point format, while `std::setprecision(2)` specifies keeping two decimal places.

In C, if you want to retain two decimal places when outputting, you can use std::setprecision and std::fixed functions, they are all defined in the header file. Here is an example:

cpp

#include <iostream>  
#include <iomanip>  
  
int main() {  
    double num = 3.141592653589793;  
    std::cout << std::fixed << std::setprecision(2) << num << std::endl;  
    return 0;  
}

In this example, std: :fixed sets the output format to a fixed decimal point format, and std::setprecision(2) sets the number of digits retained after the decimal point to 2. In this way, the output result is 3.14.

In addition, you also need to note that although std::setprecision sets the number of digits after the decimal point, it will not be rounded. If you need to round, you can use the std::round function, which is defined in the header file. Here is an example:

cpp

#include <iostream>  
#include <iomanip>  
#include <cmath>  
  
int main() {  
    double num = 3.141592653589793;  
    num = std::round(num * 100.0) / 100.0;  
    std::cout << std::fixed << std::setprecision(2) << num << std::endl;  
    return 0;  
}

In this example, we first Multiply num by 100, then round, and finally divide by 100 to get the result to two decimal places. The output is still 3.14.

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