How do I avoid checking everything with a different If using for loops?

In CPP, how do I avoid walls of ifs using for loops?
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Code Example:

    if(masiv[0][0] == 'X'){
        masiv[0][0] = '1';
    }
    if(masiv[0][1] == 'X'){
        masiv[0][1] = '2';
    }
    if(masiv[0][2] == 'X'){
        masiv[0][2] = '3';
    }
    if(masiv[1][0] == 'X'){
        masiv[1][0] = '4';
    }
    if(masiv[1][1] == 'X'){
        masiv[1][1] = '5';
    }
    if(masiv[1][2] == 'X'){
        masiv[1][2] = '6';
    }
    if(masiv[2][0] == 'X'){
        masiv[2][0] = '7';
    }
    if(masiv[2][1] == 'X'){
        masiv[2][1] = '8';
    }
    if(masiv[2][2] == 'X'){
        masiv[2][2] = '9';
    }

>Solution :

for (int y = 0; y < 3; ++y) {
  for (int x = 0; x < 3; ++x) {
    if (masiv[y][x] == 'X') {
      masiv[y][x] = '1' + 3 * y + x;
    }
  }
}