How can I get the common digits of two int in C ? Example: (1234, 41567) --> 1 4-CodePudding

Given two int I want to get all the common digits and print out them separated by spaces.

So for example, if int x=1234; int y=41567; then I want to print out: 1 4.

This is my code. It does not work properly. When I run it, it prints 0 1 2 3 4 5 then stops.

I don't want to use vector nor arrays.

void problema3() {
    int x, y, kX=0, kY=0;
    cout << "x="; cin >> x;
    cout << "y="; cin >> y;
    int cx = x;
    int cy = y;
    for (int i = 0; i < 10; i  ) {
        kX = 0; 
        kY = 0;
        x = cx;
        y = cx;
        while (x != 0 || kX==0) {
            if (x % 10 == i) kX=1;
            x /= 10;
        }
        while (y != 0 || kY == 0) {
            if (y % 10 == i) kY=1;
            y /= 10;
        }
        if (kX == 1 && kY == 1) cout << i << ' ';
    }
 }


int main()
{
    problema3();
    return 0;
}

CodePudding user response：

If you're allowed to use std::set then you can do what you want as follows:

#include <iostream>
#include <set>

void print(int x, int y)
{
    int individual_number1 = 0, individual_number2 = 0;
    
    std::set<int> myset;
    
    int savey = y;//this will be used to reset y when the 2nd do while loop finishes
  
    do 
    {
       individual_number1 = x % 10; 
      
       do 
       {
         individual_number2 = y % 10;
        
         if(individual_number1 == individual_number2)
         {
             myset.insert(individual_number1);
             break;
         }
         y = y / 10;
       }while( y > 0);
       
       y = savey;
       x = x / 10;
   } while (x > 0);
   
    //print out the element of the set
    for(int i: myset)
    {
        std::cout<<i<<" ";
    }
}
int main()
{
    int x = 1234, y = 41567;
    
    print(x, y);
   
   
    
    return 0;
}

The output of the above program is as follows:

1 4

which can be seen here.

CodePudding user response：

Your main bug is when assigning copies of cy.

//...
for (int i = 0; i < 10; i  ) {
    //...
    x = cx;
    y = cx;    // <-- BUG!  should read y = cy;

But that's not the only bug in your program.

Your digit detection logic is wrong. In particular, zero is not handled correctly, and since you did not put that reusable code in a function, your program is way more complex than it needs.

Here's the corrected logic for digit detection.

// checks if base 10 representation of a positive integer contains a certain digit (0-9)
bool hasDigit(int x, int d)
{
    do
    {
        if (x % 10 == d)
            return true;
        x /= 10;
    } while (x != 0); 
    return false; 
}

Your main loop then becomes:

// assuming int x, y as inputs.
// ...

for (int i = 0; i < 10;   i) 
{
    if (hasDigit(x, i) && hasDigit(y, i))
        std::cout << i << ' ';
}

Which leaves very little room for bugs.

You can play with the code here: https://godbolt.org/z/5c5brEcEq