Comparing digits and finding numbers with same digits - c++

Question

here is my problem.The program needs to print out the number of numbers in the range between m and n which have different digits.For example:m=97,n=104;output:5.I seem to have problem with comparing the numbers and finding a way to check if there are 2 same digits.Here what I've written up till now:
enter code here
#include <iostream>
using namespace std;
int main()
{
int m, n;
cout << "m=";
cin >> m;
cout << "n=";
cin >> n;
for (int i = m; i <=n; ++i)
{
if (i >= m && i <= n)
{
while (i > 0)
{
m=i%=10;
i/= 10;
cout << m;
}
}
}
system("pause");
return 0;
}
If you can give me the easiest possible solution.Thanks in advance

Answer 1

The best way to do this is to break it down into two parts. The main part is responsible for incrementing the number set (which is easiest if the variables are integers) and the second part is to compare each part of the number to see if a number has been repeated (which is best done as a string).
So first I would define the method responsible for determining if the value has all distinct digits:
bool hasDistinctDigits(int m) {
string number = to_string(m);
for (string::size_type i = 0; i < number.size(); i++) {
for (string::size_type j = i + 1; j < number.size(); j++) {
if (number[i] == number[j]) return false;
}
}
return true;
}
This should be pretty easy to understand. First we need to convert the number to a string. Then we use 2 loops to determine if a character is repeated in a higher index. For example, with the number 102, it will compare the following sets: {1, 0}, {1,2}, {0, 2}
Then in the main function, I would call it like this:
int main()
{
int m, n, matched = 0;
cout << "m=";
cin >> m;
cout << "n=";
cin >> n;
for (int current = m; current <= n; ++current){
if (hasDistinctDigits(current)) {
cout << current << " is distinct" << endl;
matched++;
}
}
cout << "Total Matched: " << matched << endl;
system("pause");
return 0;
}