Formatting C++ console output

Question

I\'ve been trying to format the output to the console for the longest time and nothing is really happening. I\'ve been trying to use as much of iomanip as I can

Answer 1

Boost has a format library that allows you to easily format the ourput like the old C printf() but with type safety of C++.

Remember that the old C printf() allowed you to specify a field width. This space fills the field if the output is undersized (note it does not cope with over-sized fields).

#include 
#include 
#include 

struct X
{  // this structure reverse engineered from
   // example provided by 'Mikael Jansson' in order to make this a running example

    char*       name;
    double      mean;
    int         sample_count;
};
int main()
{
    X   stats[] = {{"Plop",5.6,2}};

    // nonsense output, just to exemplify

    // stdio version
    fprintf(stderr, "at %p/%s: mean value %.3f of %4d samples\n",
            stats, stats->name, stats->mean, stats->sample_count);

    // iostream
    std::cerr << "at " << (void*)stats << "/" << stats->name
              << ": mean value " << std::fixed << std::setprecision(3) << stats->mean
              << " of " << std::setw(4) << std::setfill(' ') << stats->sample_count
              << " samples\n";

    // iostream with boost::format
    std::cerr << boost::format("at %p/%s: mean value %.3f of %4d samples\n")
                % stats % stats->name % stats->mean % stats->sample_count;
}