int isprint(int chr);

tests if character is printable

#include <iostream> /* including standard library */
#include <string>
#include <cctype>
 
using namespace std;
int main ( void )
{
  int i;
  string str="Test -!&%1";
  for (i=0; i <= 11;i++)
    {
     if ( isprint(str[i]) != 0 )
      {
        cout << "Character " << i << " is printable char" << endl;
      }
    }
  return 0;
}

  Character 0 is printable char
  Character 1 is printable char
  Character 2 is printable char
  Character 3 is printable char
  Character 4 is printable char
  Character 5 is printable char
  Character 6 is printable char
  Character 7 is printable char
  Character 8 is printable char
  Character 9 is printable char