如何正确打印带有边距的长字符串（setw（））？

Question

My string is hmm, 350 chars long. I need to center it in the console so it has same margins from the left and right side.

When I try to setw() on this, I get an output like this (only the beginning is with a margin).

          aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa

What I'm trying to achieve:

             aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
             aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
             aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa

My code looks like this (only for the left side, I didn't even try for the second one yet):

out << left << setw(20) << " " << longString << endl;

If someone knows how to achieve my goal, I'll be grateful!

Answer 1

If you know the linewidth it is rather simple:

#include <iostream>
#include <string>
#include <iomanip>

int main(){
    std::string longstring = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa";
    int margin = 5;
    int linewidth = 10;
    int pos = 0;
    while (pos < longstring.size()){
        std::cout << std::setw(linewidth) 
                  << longstring.substr(pos,linewidth-margin) << std::endl;
        pos+= linewidth-margin;
    }
}