Use the storage keyword in examples

docs/solidity-by-example.rst

@@ -101,7 +101,7 @@ of votes.
         /// Delegate your vote to the voter `to`.
         function delegate(address to) {
             // assigns reference
-            Voter sender = voters[msg.sender];
+            Voter storage sender = voters[msg.sender];
             require(!sender.voted);
 
             // Self-delegation is not allowed.
@@ -141,7 +141,7 @@ of votes.
         /// Give your vote (including votes delegated to you)
         /// to proposal `proposals[proposal].name`.
         function vote(uint proposal) {
-            Voter sender = voters[msg.sender];
+            Voter storage sender = voters[msg.sender];
             require(!sender.voted);
             sender.voted = true;
             sender.vote = proposal;

docs/types.rst

@@ -743,7 +743,7 @@ shown in the following example:
         }
 
         function contribute(uint campaignID) payable {
-            Campaign c = campaigns[campaignID];
+            Campaign storage c = campaigns[campaignID];
             // Creates a new temporary memory struct, initialised with the given values
             // and copies it over to storage.
             // Note that you can also use Funder(msg.sender, msg.value) to initialise.
@@ -752,7 +752,7 @@ shown in the following example:
         }
 
         function checkGoalReached(uint campaignID) returns (bool reached) {
-            Campaign c = campaigns[campaignID];
+            Campaign storage c = campaigns[campaignID];
             if (c.amount < c.fundingGoal)
                 return false;
             uint amount = c.amount;