Rounding float in ToString() function?

Question

So I have a form with a label which is supposed to display float value, the problem is that I need to have that number rounded to 2 decimal places whatever happens:

label1->Text = System::Convert::ToString( (float)((float)temperature/204.6) );

I tried looking for few hours but as I found there is no method for direct rounding of that beast equation and as far as I know no way to tell ToString() to round the thing to 2 decimals.

Is there any easy way to round the result to 2 decimal places inside ToString method?

Answer 1

这很简单：

String^ s = String::Format("{0:N2}", temperature/204.6); 

Answer 2

Is there any easy way to round the result to 2 decimal places inside ToString method?

No, not with std::tostring() and if you want to preserve trailing zeroes. Use a std::ostringstream with appropriate I/O manipulators instead:

 std::ostringstream oss;
 oss << std::fixed << std::setprecision(2) << (temperature/204.6);
 label1->Text = oss.str();

Answer 3

您不能将结果乘以100，转换为int，然后再除以100并转换为浮点数吗？

Answer 4

Here is JavaScript equivalent of toFixed:

#include <iostream>

std::string ToFixed(double number, size_t digits)
{
    char format[10];
    char str[64];
    sprintf_s(format, "%%0.%zdf", digits);
    return std::string(str, sprintf_s(str, format, number));
}

int main()
{
    std::cout << ToFixed((double)12345 / 204.6, 2) << std::endl;

    return 0;
}

Prints:

60.34