Insertion in singly linked list at beginning

Inserting a new element into a singly linked list at beginning is quite simple. We just need to make a few adjustments in the node links. There are the following steps which need to be followed in order to inser a new node in the list at beginning.

• Allocate the space for the new node and store data into the data part of the node. This will be done by the following statements.

• Make the link part of the new node pointing to the existing first node of the list. This will be done by using the following statement.

• At the last, we need to make the new node as the first node of the list this will be done by using the following statement.

Algorithm

• Step 1: IF PTR = NULL

Write OVERFLOW
    Go to Step 7
    [END OF IF]

• Step 2: SET NEW_NODE = PTR
• Step 3: SET PTR = PTR → NEXT
• Step 4: SET NEW_NODE → DATA = VAL
• Step 5: SET NEW_NODE → NEXT = HEAD
• Step 6: SET HEAD = NEW_NODE
• Step 7: EXIT

C Function

Output

Enter the item which you want to insert?  12    Node inserted    Press 0 to insert more ?  0    Enter the item which you want to insert?  23    Node inserted    Press 0 to insert more ?  2