q1.2.cpp

#include <assert.h>
#include <ctype.h>
#include <iostream>
#include <string.h>
#include <vector>

using namespace std;
void character_frequency(char *input_string, unsigned int *counter,
                         vector<int> *non_zero_indices) {
  int string_length = strlen(input_string);
  char c;
  int index;
  for (int i = 0; i < string_length; i++) {
    c = toupper(input_string[i]);
    index = (int)c;
    if (*(counter + index) == 0)
      non_zero_indices->push_back(index);
    (*(counter + index))++;
  }
}

int main(int argc, char **argv) {
  assert(argc > 1);
  vector<int> non_zero_indices1, non_zero_indices2;
  unsigned int counter1[127] = {0}, counter2[127] = {0};
  char *input_string1 = argv[1];
  char *input_string2 = argv[2];
  character_frequency(input_string1, counter1, &non_zero_indices1);
  character_frequency(input_string2, counter2, &non_zero_indices2);

  if (non_zero_indices1.size() != non_zero_indices2.size())
    goto NEGATIVE;

  else {
    for (auto it = non_zero_indices1.begin(); it != non_zero_indices1.end();
         it++) {
      if (counter1[*it] != counter2[*it])
        goto NEGATIVE;
    }
    goto POSITIVE;
  }

NEGATIVE : {
  cout << "both the strings ARE NOT permutations of each other\n";
  goto PRINT_FREQUENCIES;
}

POSITIVE : { cout << "both the strings ARE permuations of each other\n"; }

PRINT_FREQUENCIES : {
  cout << "printing characters and their frequencies for string1\n";
  for (auto it = non_zero_indices1.begin(); it != non_zero_indices1.end();
       it++) {
    cout << char(*it) << ": " << counter1[*it] << '\n';
  }

  cout << "printing characters and their frequencies for string2\n";
  for (auto it = non_zero_indices2.begin(); it != non_zero_indices2.end();
       it++) {
    cout << char(*it) << ": " << counter2[*it] << '\n';
  }
}

  return 0;
}