#include <iostream>
#include <cmath>
 
#define LOWER_CASE_DIFF 'a'-'A'
 
using namespace std;
 
void changeSeq(string &in, int amount) {
    int i = 0;
    while (i < amount && (int)in[i] < 'a') {
        in[i] += LOWER_CASE_DIFF;
        i++;
    }
    if (i < amount) {
        in[i] -= LOWER_CASE_DIFF;
    }
    cout << in << endl;
}
int main() {
    string input = "abc";
    int diff = 'a' - 'A'; //a is always bigger than A in ASCII
    int comb = (int)pow(2,(float)input.length());
    for (int i = 1; i <= comb; i++) {
        changeSeq(input, i);    
    }
 
 
    return 0;
}

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