C Sharp goto statement for breaking the nested loop

vik20000in — Mon, 06 Apr 2009 05:33:00 GMT

Hi,

Two days back, while discussing with a friend came a small interesting (programming) situation where he wanted to stop (break) a loop which was inside another loop.

You can think of the situation as he was first looping through all the rows in a grid view and then in the entire column in the grid view. Now he was trying to look into the text of each cell, and if the text matched a given value, he needed to break from both the loop and execute the statement after the loop.

His first idea was to use a flag which will be checked in the outer loop every time to see if the value has been found in the inner loop. The code would be something like below.

bool flag = false;

for(int i = 0;i<grd.Rows.count;i++)
{
    if(flag==true)
    { break; }
    for(int j= 0;j<grd.Columns.count;j++)
    {
        if(grd.Rows[i][j].ToString() == “someValue”;
        flag = true;
        Break;
    }
}

// Statement to executed after loop.

I am sure most of us have faced some or other situation where we had some requirement like this and the solution provided was also similar.

The code does the work that we want it to do, but if you look deeply it has a problem. I have to check the value of the flag for each time there is a loop for the row and also to maintain a tedious flag for a just breaking the loop.

The same work can be easily done without using a flag, by using a goto statement like this.

for(int i = 0;i<grd.Rows.count;i++)
{
    for(int j= 0;j<grd.Columns.count;j++)
    {
        if(grd.Rows[i][j].ToString() == “someValue”;
        {
            goto foundcell;
        }
}
foundcell:

// Statement to executed after loop.

This way, I could break from both (if required even more than 2 loops) the loops easily without maintaining any flag with the help of a goto statement.

Remember the goto statement should only be used when we have nested loops. If you have only one loop than its best to use the break keyword to stop, break the loop.

Vikram

Vikram Lakhotia : Goto

C Sharp goto statement for breaking the nested loop