How to change the value of a <c:set> tag in a <c:foreach> tag
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I have list which contains some objects.
The objects have a hours fields.
in the <c:foreach> i am iterating the list and fetching the objects.
Now  i want to sum up the hours field of all the iterated objects.
 
I was working like this but it gave me an error
 javax.el.ELException: Failed to parse the expression [${attendance.Hours += attendance.Hours }

    <c:forEach var="attendance" items="${list }"
								varStatus="rowCounter1">
								<tr>
									<td><c:out value="${rowCounter1.count}"></c:out></td>
									<td><c:out value="${attendance.date }"></c:out></td>
									<td><c:out value="${attendance.inTime }"></c:out></td>
									<td><c:out value="${attendance.outTime }"></c:out></td>
									<td><c:out value="${attendance.interval }"></c:out></td>
									
									<c:set var="totalHours" value="${attendance.Hours += attendance.Hours }" target="${attendance }"></c:set>
										
								<tr>
							</c:forEach>