Source code in the awk programming language

function is_palindro(s)
{
  if ( s == reverse(s) ) return 1
  return 0
}


function is_palindro_r(s)
{
  if ( length(s) < 2 ) return 1
  if ( substr(s, 1, 1) != substr(s, length(s), 1) ) return 0
  return is_palindro_r(substr(s, 2, length(s)-2))
}


BEGIN {
  pal = "ingirumimusnocteetconsumimurigni"
  print is_palindro(pal)
  print is_palindro_r(pal)
}