在codeigniter中切换案例

I am using the codeigniter framework.I have a switch-case problem in view where the switch case do not function. The $total_Assessment do not grouped according to marks range, all value of the $grade are the same. Hope someone can correct my mistake.

Here is my view function:

  <?php $number=1;$grade=null;$pointer=0;$level=null;?>
                 <?php foreach ($query as $data):?>
                 <tr>
                     <td><?php echo $number ?></td>
                     <td><?php echo $data->Matric_No; ?></td>
                     <td><?php echo $data->Student_Name; ?></td>
                     <td><?php echo $data->Result_Mark_1; ?></td>
                     <td><?php echo $data->Result_Mark_2; ?></td>
                     <td><?php echo $data->Result_Mark_3; ?></td>
                     <td><?php echo $data->Result_Mark_4; ?></td>
                     <td><?php echo $data->Result_Mark_5; ?></td>

                     <?php $total_Assessment=$data->Result_Mark_1+$data-Result_Mark_2+$data->Result_Mark_3+$data->Result_Mark_4+$data->Result_Mark_5 ?>
                     <td><?php echo $total_Assessment ?></td>

                     <?php
                     switch ($total_Assessment)
                     {
                         case "$total_Assessment>=80":
                             $grade="A";
                             break;

                         case "$total_Assessment>=75":
                             $grade="A-";
                             break;

                         case "$total_Assessment>=70":
                             $grade="B+";
                             break;

                         case "$total_Assessment>=65":
                             $grade="B";
                             break;

                         case "$total_Assessment>=60":
                             $grade="B-";
                             break;

                         case "$total_Assessment>=55":
                             $grade="C+";
                             break;

                         case "$total_Assessment>=50":
                             $grade="C";
                             break;

                         case "$total_Assessment>=45":
                             $grade="C-";
                             break;

                         case "$total_Assessment>=40":
                             $grade="D";
                             break;

                         default:
                             $grade="F";

                     }
                     ?>

                     <td><?php echo $grade?></td>

Thank you.

Try to remove the double quotes like this:

case "$total_Assessment>=70":

to this:

case $total_Assessment>=70:

Hope it will help.

I don't know what you want to do but we can find this in your code:

$total_Assessment=$data->Result_Mark_1+$data-Result_Mark_2+$data->Result_Mark_3+$data->Result_Mark_4+$data->Result_Mark_5

We see additions and subtractions so $total_Assessment must be a number.

switch ($total_Assessment)
{
    case "$total_Assessment>=80":

Oh, wait! Is $total_Assessment supposed to be a string with PHP code? That's just not possible!

I suspect you want this:

if($total_Assessment){
}elseif($total_Assessment>=75){
}
...

I also think the first line I quote contains several errors: $data-Result_Mark_2? Do you really have a constant called Result_Mark_2? Have you configured your development box to help you with error messages?