Why is clang-tidy giving me an uninitialized error for this c++ code?

I don't understand why there is a problem with my code. I've made sure to initialize every value in my 2D array, so there shouldn't be an uninitialized value error anywhere!

Note: I cannot use std::vector for this project. I'm also using different functions instead of std::min because I'm not allowed to import algorithm for this project.

This is the error reported by clang-tidy:

2nd function call argument is an uninitialized value

Here is my code (error only occurs on line 17):

int** SeamCarver::CarvingSeamVertical() const {
  int** energies = new int*[height_];
  for (unsigned int row = 0; row < height_; row++) {
    energies[row] = new int[width_];
    for (unsigned int col = 0; col < width_; col++) {
      energies[row][col] = 0; // initializes every value in the 2D array to zero
    }
  }
  for (unsigned int col = 0; col < width_; col++) {
    energies[height_ - 1][col] = this->GetEnergy(height_ - 1, (int)col);
  }

  for (int row = height_ - 2; row >= 0; row--) {
    for (int col = 0; col < width_; col++) {
      int best = 0;
      if (col == 0) { //error occurs here v
        best = FindMinTwo(energies[row + 1][col], energies[row + 1][col + 1]);
      } else if (col == width_ - 1) {
        best = FindMinTwo(energies[row + 1][col - 1], energies[row + 1][col]);
      } else {
        best = FindMinThree(energies[row + 1][col - 1],
                            energies[row + 1][col],
                            energies[row + 1][col + 1]);
      }
      energies[row][col] = this->GetEnergy(row, col) + best;
    }
  }
  return energies;
} // energies is properly deallocated by the function that uses it

I've tried changing the ints to unsigned ints, but the error didn't go away. I also should not encounter out-of-bounds access errors, since row starts at height - 2 and the highest value of row accessed within the loop is height - 1.

For some reason, adding a statement which prints every value in the array makes the error go away.

clang-tidy doesn't make assumptions for you. For example, it doesn't assume that width_ is greater than 1. And indeed, if width_ == 1, you get a bunch of problems and clang-tidy warns about some of them.

Add assert(width_ > 1) at the beginning, and the error will go away. Or, if you are not willing to assert that, revise your algorithm to correctly handle the case of width_ <= 1.