just not geeting at

i want to convert an input file into outputfile.the output must contain every unique character with the no. of its occurence aginst it.not sure what to do.thanx in advance.

hint: use an array of long's, 256 elements long...

Code:

---

long t[256] = {0};
int ch;
  .
  .
  .
t[ch]++;

  .
  .
  .

---

but how do i determinr the character to increment ?