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Algorithm to insert an element in a queue

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Algorithm to insert an element in a queue

Step 1: IF REAR = MAX-1 
           Write OVERFLOW 
           Goto step 4 
        [END OF IF] 
Step 2: IF FRONT=-1 and REAR=-1 
           SET FRONT = REAR = 0
        ELSE
           SET REAR = REAR+1 
        [END OF IF] 
Step 3: SET QUEUE[REAR] = NUM 
Step 4: EXIT

Explanation

• In Step 1, we first check for the overflow condition.
• In Step 2, we check if the queue is empty. In case the queue is empty, then both FRONT and REAR are set to zero, so that the new value can be stored at the 0th location. Otherwise, if the queue already has some values, then REAR is incremented so that it points to the next location in the array.
• In Step 3, the value is stored in the queue at the location pointed by REAR.

 

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