Refactor linked list and improve array addition logic

Appending_Node.c

@@ -1,69 +1,69 @@
-#include<stdio.h>
-#include<stdlib.h>
-void append();
-struct node
+#include <stdio.h>
+#include <stdlib.h>
+
+typedef struct node
 {
     int data;
     struct node *link;
-};
-struct node *root;
+} node;
+
+node *append(node *);
+void print(node *);
+
 int main()
 {
-    root=(struct node*)malloc(sizeof(struct node));
+    node *root=NULL;
+    node *current=NULL;
+    current = (node *)malloc(sizeof(node));
 
     printf("ROOT 1 DATA:");
-    scanf("%d", &root->data);
-    root->link=NULL;
-
-    struct node*current;
-    current=(struct node*)malloc(sizeof(struct node));
-
-
-    printf("ROOT 2 DATA:");
-    scanf("%d", &current->data);
-    current->link=NULL;
-    root->link=current; // this will store the address of the second node into the link part of the first node
-
-    current=malloc(sizeof(struct node));
-
-    printf("ROOT 3 DATA:");
     scanf("%d", &current->data);
-    current->link=NULL;
-    root->link->link=current; // this will store the base address of the third node into the link part of the second node
+    current->link = NULL;
+    root = current; // this will store the address of the second node into the link part of the first node
 
     printf("APPENDING NODE:\n");
-    append();  // now the user will be prompted for appending the element to the last of the linked list
-
+    root = append(root); // now the user will be prompted for appending the element to the last of the linked list
+    print(root);
+    return 0;
 }
 
-void append()
+node *append(node *root)
 {
-    struct node *temp;
-    temp=(struct node*)malloc(sizeof(struct node));
+    node *temp=NULL;
+    temp = (node *)malloc(sizeof(node));
+
     printf("ENTER NODE DATA:");
     scanf("%d", &temp->data);
+    temp->link = NULL;
 
-    if(root==NULL)
+    if (root == NULL)
     {
-        root=temp; // we are checking if the linked list is empty then this will be the first node to be inserted in the linked list
+        root = temp; // we are checking if the linked list is empty then this will be the first node to be inserted in the linked list
     }
 
     else
     {
-        struct node *ptr;  // used for traversing through nodes
-        ptr=root;
-        while(ptr->link!=NULL)
+        node *ptr; // used for traversing through nodes
+        ptr = root;
+        while (ptr->link!= NULL)
         {
-            ptr=ptr->link;
+            ptr = ptr->link;
         }
-        ptr->link=temp; // this will connect the last node with the temp node which we created before
+        ptr->link = temp; // this will connect the last node with the temp node which we created before
     }
 
-    printf("PRINTING DATA IN ALL NODES\n");
-
-    printf("NODE 1: %d\n", root->data);
-    printf("NODE 2: %d\n", root->link->data);
-    printf("NODE 3: %d\n", root->link->link->data);
-    printf("NODE 4: %d\n", root->link->link->link->data);
+    return root;
+}
 
+void print(node *root)
+{
+    node *ptr;
+    ptr = root;
+    printf("PRINTING DATA IN ALL NODES:\n");
+    while (ptr->link != NULL)
+    {
+        printf("%d->",ptr->data);
+        ptr = ptr->link;
+    }
+    printf("%d", ptr->data);
 }

Calculator.c

@@ -28,8 +28,8 @@ int main()
         result=a/b;
         printf("The Division Is %d", result);
         break;
-        default:
-    printf("Please Enter a valid Operator");
+    default:
+        printf("Please Enter a valid Operator");
         break;
     }
     return 0;

Take input from user

@@ -10,7 +10,7 @@ int main()
 
     // Performs all arithmetic operations   
     sum = no1 + no2;  
-    sub = no - no2;  
+    sub = no1 - no2;  
     mult = no1 * no2;  
     div = (float)no1 / no2;  
     mod = no1 % no2;  
@@ -21,5 +21,5 @@ int main()
     printf("The product of the entered numbers : %d\n", mult);  
     printf("The quotient of the entered numbers : %f\n", div);  
     printf("Mod = %d\n", mod); //remainder 
-    
+  return 0;
 } 

additionarray.c

@@ -3,22 +3,22 @@ int main()
 {
   int arr1[5],arr2[5],arr3[5],i;
   printf("Enter 5 numbers of arr1:");
-  for(i=0;i<=4;i++)
+  for(i=0;i<5;i++)
   {
     scanf("%d",&arr1[i]);//Taking input from the user for the first array.
   }
   printf("Enter 5 numbers of arr2:");
-  for(i=0;i<=4;i++)
+  for(i=0;i<5;i++)
   {
     scanf("%d",&arr2[i]);//Taking input from the user for the second array.
   }
-  for(i=0;i<=4;i++)
+  for(i=0;i<5;i++)
   {
     arr3[i]=arr1[i]+arr2[i];//Addition of the two arrays.
   }
   printf("Addition of two array:");
-  for(i=0;i<=4;i++)
+  for(i=0;i<5;i++)
   {
-      printf("%d\t",arr3[i]);//Printing the new array.
+      printf("%d  ",arr3[i]);//Printing the new array.
   }
 }

calculator.c

@@ -28,8 +28,8 @@ int main()
         result=a/b;
         printf("The Division Is %d", result);
         break;
-        default:
-    printf("Please Enter a valid Operator");
+    default:
+        printf("Please Enter a valid Operator");
         break;
     }
     return 0;

difference.c

@@ -24,6 +24,7 @@ int main()
             break;
     default:
         printf("Wrong Choice!!!");
+        break;
   }
   return 0;
 }

even.c

@@ -1,17 +1,17 @@
-//C program to find out a number is even or not.
+// C program to find out a number is even or not.
 
-#include<stdio.h>
+#include <stdio.h>
 void main()
-{ int numb,i;
-printf("Enter a number:");
-scanf("%d",&numb);
-if(numb%2==0) // condition to check even logic
 {
-printf("A even number");
-}
-else
-{
-printf("A odd number");
-}
-
+    int numb, i;
+    printf("Enter a number:");
+    scanf("%d", &numb);
+    if (numb % 2 == 0) // condition to check even logic
+    {
+        printf("A even number");
+    }
+    else
+    {
+        printf("A odd number");
+    }
 }

swapping.c

@@ -1,6 +1,6 @@
 //C program to swap the values of two numbers.
 
-#include<stdio>
+#include<stdio.h>
 int main()
 {
   int x,y,t;
@@ -11,4 +11,5 @@ int main()
   x=y;
   y=t;
   printf("The swapped values of x=%d and y=%d",x,y);
+  return 0;
 }

table.c

@@ -10,4 +10,5 @@ int main()
   {
     printf("%d * %d = %d\n",n,i,n*i);
   }
+  return 0;
 }

table10num.c

@@ -4,14 +4,14 @@
 int main()
 {
   int i,j,num;
-  printf("Enter a number:\n");
-  scanf("%d",&num);
   printf("Table of 10 numbers\n");
   for(i=1;i<=10;i++)
   {
     for(j=1;j<=10;j++)
     {
       printf("%d\t",i*j);
     }
+    printf("\n");
   }
+  return 0;
 }

table2.c

@@ -10,4 +10,5 @@ int main()
   {
     printf("%d\n",n*i);
   }
+  return 0;
 }