rosalind_counting_DNA_nucleotides.nim

const data = "AGCTTTTCATTCTGACTGCAACGGGCAATATGTCTCTGTGTGGATTAAAAAAAGAGTGTCTGATAGCAGC"

var A, C, G, T = 0

for letter in data:
  case letter
  of 'A': inc A
  of 'C': inc C
  of 'G': inc G
  of 'T': inc T
  else: discard

echo A, " ", C, " ", G, " ", T