Question

C PROGRAMMING: SHIFT TYPEDEFS INSIDE OF AN ARRAY.

I have an array of NODES,

NODE nodes[513];

typedef struct node {
int weight;   
} NODE;

I have a value called int num_nodes which gives the number of positions in that array which are filled.

What I need to do:

there is a value inside of nodes[0], but there are other values in the node array which can be found at index nodes[256] to nodes[256+num_nodes]. I need to shift all of these nodes that are in the far part of the array so that they appear after node[0]. the nodes which are unused have their weight set to -1. i need to shift till there are no -1 between root and the used nodes

How?

Also, I am NOT ALLOWED TO USE ARRAY BRACKETS [ ] ONLY POINTERS to navigate the array.

Answer 1

//C program

#include<stdio.h>

typedef struct node {
int weight;   
} NODE;
NODE nodes[513];

int main(){
   int i;
   (nodes+0)->weight = 100;
   int num_nodes = 20;;
   for(i=1;i<513;i++)(nodes+i)->weight = -1;
   for(i =256;i<256+num_nodes;i++)(nodes+i)->weight = i+num_nodes;
  
   printf("array before shifting\n ");
  
   for(i=0;i<513;i++){
       printf("%d ",(nodes+i)->weight);
       if(i!=0&&i%10==0)printf("\n");
   }
   for(i=1;i<=num_nodes;i++){
       (nodes+i)->weight = (nodes+255+i)->weight;
       (nodes+255+i)->weight= -1;
   }
   printf("\n\narray after shifting\n ");
  
   for(i=0;i<513;i++){
       printf("%d ",(nodes+i)->weight);
       if(i!=0&&i%10==0)printf("\n");
   }
   return 0;
}