break in For Loop (have some issues)-CodePudding

So im currently using EPPLUS in C#, trying to get some data from an excel file. It's working BUT, break; makes my head go "boom-boom". There are segments in my for loop that if i put the break; or get rid of it, stops my programm from going through and just freezes it. So i'm stuck at this segment of code and it's just freezes my app. Can you help me somehow? (please dont call me stupid or anything like that, i'm learning)

for (int row = 2; row <= end.Row;)
{ // Row by row...
    for (int col = start.Column; col <= end.Column; col  )
    { // ... Cell by cell...
        string cellValue = ws.Cells[row, col].Text;

        if (String.Compare(cellValue, "Номер Машины", true) == 0)
        {
            for (int row_ = row   1; row_ <= end.Row;)
            {
                for (int col_ = col; col_ <= end.Column;)
                {
                    string cellValue_ = ws.Cells[row_, col_].Text;
                    MessageBox.Show(cellValue_);


                    for (int row__ = row_   1; row__ <= end.Row;)
                    {
                        for (int col__ = col_; col__ <= end.Column;)
                        {
                            string cellValue__ = ws.Cells[row__, col__].Text;
                            if (cellValue__ != string.Empty)
                            {
                                MessageBox.Show(cellValue__);
                                break;
                            }
                            
                        }
                        break;
                    }
                    break;
                }
                break;
            }
            
        }
    }
    break;
}

I was playing with "break;" but it just made everything worse and thank God i had a backup

CodePudding user response：

These breaks exit the current loop immediately. So, all of these outer loops will loop only once. You cannot exit all the loops from the innermost one using breaks.

This is rare case where using a goto statement makes sense:

// (Code simplified)
for (int row_ = row   1; row_ <= end.Row; row_  ) {
    for (int col_ = col; col_ <= end.Column; col_  ) {
        for (int row__ = row_   1; row__ <= end.Row; row__  ) {
            for (int col__ = col_; col__ <= end.Column; col__  ) {
                if (cellValue__ != string.Empty) {
                    MessageBox.Show(cellValue__);
                    goto exit_all;
                }
            }
        }
    }
}
exit_all:

If you want to return a result from the inner-most loop, you can put this code into a method or local function and exit all the loops and the method with a return statement:

// (Code simplified)
string GetResult()
{
    for (int row_ = row   1; row_ <= end.Row; row_  ) {
        for (int col_ = col; col_ <= end.Column; col_  ) {
            for (int row__ = row_   1; row__ <= end.Row; row__  ) {
                for (int col__ = col_; col__ <= end.Column; col__  ) {
                    if (cellValue__ != string.Empty) {
                        return cellValue__;
                    }
                }
            }
        }
    }
}

I also added all the missing loop_variable as @jmcilhinney and @RetiredNinja have pointed out in their comments. Note that not incementing the loop variables let's the loops loop forever (unless they are exited with break). This is what caused the freeze.