Output a deciman number (double) in a string

ROOT
1

I want to output a number in a string, and was using the standard way:

sprintf(title,“selection > %d”, number),

but this only outputs the nearest integer.

I tried to replace %d with %f or %lf but these only made root crash.

Any ideas on how to output the entire number and not just the nearest integer?

2

It depends what “number” is. If you want to use %g or %f “number” must be a float or a double. Better cast it is you are not sure what is it. Here is a small example :

void print_pi()
{
   // 1st way:
   char pi_string[20];
   double pi = 3.14159;
   sprintf(pi_string, "pi = %g",(double)pi);
   printf("%s\n", pi_string);

   //2nd way:
   printf("%s\n", Form("pi = %g",(double)pi));
}
3

You’d better use snprintf instead of sprintf: { char title[100] = "some old value"; std::cout << "title = " << title << std::endl; double number = 1.234567; snprintf(title, sizeof(title), "selection > %g", number); std::cout << "title = " << title << std::endl; }