DMA basics

codes/dma/calloc.c

@@ -0,0 +1,27 @@
+#include<stdio.h>
+#include<stdlib.h>
+
+int main(){
+    int number;
+    float *p;
+    printf("Enter the number of blocks that you want to allocate:");
+    scanf("%d",&number);
+
+    p=(float*)calloc(number,sizeof(float));
+    //here it allocates with respect to the number
+
+    if(p==NULL){
+        printf("No space has been allocated");
+    }
+    for(int i=0;i<number;++i){
+        printf("p[%d]=",i);
+        scanf("%f",p+i);
+        //didnt use & because p+i it is directly referencing to the memory
+    }
+    //displaying all the elements in the dynmaically allocated array
+    for(int i=0;i<number;++i){
+        printf("%f\t",*(p+i));
+    }
+    free(p);
+    return 0;
+}

codes/dma/malloc.c

@@ -0,0 +1,21 @@
+#include<stdio.h>
+#include<stdlib.h>
+
+int main(){
+    int i, sum=0, *p;
+    int n;
+    printf("Enter the number of int spaces that you want to dynamically allocate:\n");
+    scanf("%d",&n);
+    p= (int*)malloc(n*sizeof(int));
+    if(p==NULL){
+        printf("No space was dynamically allocated");
+    }
+    for(int i=0;i<n;++i){
+        printf("p[%d]=\n",i);
+        scanf("%d",p+i);
+        sum+=*(p+i);
+    }
+    printf("\nNow the sum of all the items of the array is %d",sum);
+    free(p);
+    return 0;
+}

codes/queue/circularqueue.c

@@ -0,0 +1,97 @@
+// Circular Queue implementation in C
+
+#include <stdio.h>
+
+#define SIZE 5
+
+int items[SIZE];
+int front = -1, rear = -1;
+
+// Check if the queue is full
+int isFull() {
+  if ((front == rear + 1) || (front == 0 && rear == SIZE - 1)) return 1;
+  return 0;
+}
+
+// Check if the queue is empty
+int isEmpty() {
+  if (front == -1) return 1;
+  return 0;
+}
+
+// Adding an element
+void enQueue(int element) {
+  if (isFull())
+    printf("\n Queue is full!! \n");
+  else {
+    if (front == -1) front = 0;
+    rear = (rear + 1) % SIZE;
+    items[rear] = element;
+    printf("\n Inserted -> %d", element);
+  }
+}
+
+// Removing an element
+int deQueue() {
+  int element;
+  if (isEmpty()) {
+    printf("\n Queue is empty !! \n");
+    return (-1);
+  } else {
+    element = items[front];
+    if (front == rear) {
+      front = -1;
+      rear = -1;
+    } 
+    // Q has only one element, so we reset the 
+    // queue after dequeing it. ?
+    else {
+      front = (front + 1) % SIZE;
+    }
+    printf("\n Deleted element -> %d \n", element);
+    return (element);
+  }
+}
+
+// Display the queue
+void display() {
+  int i;
+  if (isEmpty())
+    printf(" \n Empty Queue\n");
+  else {
+    printf("\n Front -> %d ", front);
+    printf("\n Items -> ");
+    for (i = front; i != rear; i = (i + 1) % SIZE) {
+      printf("%d ", items[i]);
+    }
+    printf("%d ", items[i]);
+    printf("\n Rear -> %d \n", rear);
+  }
+}
+
+int main() {
+  // Fails because front = -1
+  deQueue();
+
+  enQueue(1);
+  enQueue(2);
+  enQueue(3);
+  enQueue(4);
+  enQueue(5);
+
+  // Fails to enqueue because front == 0 && rear == SIZE - 1
+  enQueue(6);
+
+  display();
+  deQueue();
+
+  display();
+
+  enQueue(7);
+  display();
+
+  // Fails to enqueue because front == rear + 1
+  enQueue(8);
+
+  return 0;
+}

codes/queue/priorityqueue.c

@@ -0,0 +1,106 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#define size 3
+
+void enqueue(int item);
+void dequeue();
+void show();
+int front = -1;
+int arr[size];
+int priority[size];
+int largest;
+int ans;
+
+int main()
+{
+    do
+    {
+
+        int choice, item;
+        printf("1)Enqueue\n2)Dequeue\n3)Show");
+        scanf("%d", &choice);
+        switch (choice)
+        {
+        case 1:
+            printf("\nEnter the item that you want to enqueue");
+            scanf("%d", &item);
+            enqueue(item);
+            break;
+        case 2:
+            dequeue();
+            break;
+        case 3:
+            show();
+            break;
+
+        default:
+            printf("Choose a correct input");
+            break;
+        }
+        printf("Do you want to continue?\t press 0 for yes and 1 for no\n");
+        scanf("%d",&ans);
+    } while (ans == 0);
+}
+void enqueue(int item)
+{
+    if (front == size - 1)
+    {
+        printf("not enough space\n");
+    }
+    else
+    {
+        front++;
+        arr[front] = item;
+        printf("Enter the priority of it:\n");
+        scanf("%d", &priority[front]);
+    }
+}
+void dequeue()
+{
+    int item;
+    if (front == -1)
+    {
+        printf("there is no element");
+    }
+    else
+    {
+        for (int i = 1; i < size; i++)
+        {
+            if (priority[i] > priority[i - 1])
+            {
+                if(priority[i]>priority[i+1]){
+                    largest=i;
+                }
+            }
+            else if (priority[i]<priority[i-1])
+            {
+                if(priority[i-1]>priority[i+1]){
+                    largest=i-1;
+                }
+                else{
+                    largest=i+1;
+                }
+            }
+
+        }
+        front--;
+        item=arr[largest];
+        printf("The element with the highest priority is %d",item);
+        printf("The item %d has been dequeued",item);
+        for(int i=0;i<size;i++){
+            if(item == arr[i]){
+                arr[i]=0;
+                priority[i]=0;
+            }           
+        }
+    }
+}
+
+void show()
+{
+    for (int i = 0; i < size; i++)
+    {
+        printf("%d\t", arr[i]);
+    }
+}