c++ - Subtract a number from an ASCII char -

so, i'm trying in thread, except want go backwards ascii conversion (letters only) aka, if gave number 1.

b+1 =  b+1 = (capital becomes capital)  c+2 =  z+1 = y  a+1 = z

int lower_add = ((letter - 'a' - input_int) % 26) +'a'; if ((lower_add -'a' - input_int) < 0)     lower_add = lower_add +26;

this getting it, except there cases b+1 go other non-letter ascii char.

lower_add has input_int subtracted out, don't second time. change if to:

if (lower_add < 'a')     lower_add += 26;

this still won't deal capital letters correctly, you'll need range test decide whether subtract 'a' or 'a'.

Brazell