Create Linear Queue

Linear Queue

@@ -0,0 +1,96 @@
+#include <stdio.h>
+#include <conio.h>
+#define MAX 10 // Changing this value will change length of array
+int queue[MAX];
+int front = -1, rear = -1;
+void insert(void);
+int delete_element(void);
+int peek(void);
+void display(void);
+
+int main()
+{
+      int option, val;
+      do
+      {
+            printf("\n\n ***** MAIN MENU *****");
+            printf("\n 1. Insert an element");
+            printf("\n 2. Delete an element");
+            printf("\n 3. Peek");
+            printf("\n 4. Display the queue");
+            printf("\n 5. EXIT");
+            printf("\n Enter your option : ");
+            scanf("%d", &option);
+            switch(option)
+             {
+                  case 1: insert();
+                          break;
+                  case 2: val = delete_element();
+                          if (val != -1)
+                          printf("\n The number deleted is : %d", val);
+                          break;
+                  case 3: val = peek();
+                          if (val != -1)
+                          printf("\n The first value in queue is : %d", val);
+                          break;
+                  case 4: display();
+                          break;
+             }
+         }while(option != 5);
+      getch();
+      return 0;
+}
+void insert()
+{
+      int num;
+      printf("\n Enter the number to be inserted in the queue : ");
+      scanf("%d", &num);
+      if(rear == MAX-1)
+      printf("\n OVERFLOW");
+      else if(front == -1 && rear == -1)
+      front = rear = 0;
+      else
+      rear++;
+      queue[rear] = num;
+}
+int delete_element()
+{
+      int val;
+      if(front == -1 || front>rear)
+      {
+            printf("\n UNDERFLOW");
+            return -1;
+      }
+      else
+      {
+            val = queue[front];
+            front++;
+            if(front > rear)
+            front = rear = -1;
+            return val;
+      }
+}
+int peek()
+{
+      if(front==-1 || front>rear)
+      {
+            printf("\n QUEUE IS EMPTY");
+            return -1;
+      }
+      else
+      {
+            return queue[front];
+      }
+}
+void display()
+{
+      int i;
+      printf("\n");
+      if(front == -1 || front > rear)
+            printf("\n QUEUE IS EMPTY");
+      else
+      {
+            for(i = front;i <= rear;i++)
+            printf("\t %d", queue[i]);
+      }
+}