Question

NO MALLOC & NO USE OF [ ]

C need to parse a file and update array of structs while i do it.

The program reads input from stdin byte by byte (the bytes are from 0 to 255 and each byte represents an ascii symbol value) and each time the a byte occurs it the num_occurences field in the NODE struct must increase.

this is the struct

typedef struct node {
int num_occurences;   
short symbol;   
} NODE;

this is the array

NODE *node_symb[257];

please help me, again I need to traverse stdin byte by byte and increment the value of num_occurences each time the symbol is repeated. the array is empty in the beginning. I don't know how to do this please help.

Answer 1

#define _CRT_SECURE_NO_DEPRECATE
#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>

typedef struct node {
   int num_occurences;
   short symbol;
} NODE;
int main()
{
   NODE node_symb[257];
   short byte;
   int count = 0,i=0,found=-1;
   while ((byte = fgetc(stdin)) != EOF)
   {
       if (count == 0)
       {
           //node_symb[count]= (NODE*)malloc(sizeof(NODE));
           (node_symb + count)->symbol = byte;
           (node_symb+count)->symbol = byte;
           (node_symb + count)->num_occurences = 1;
           ++count;
       }
       else
       {
          
           for (i = 0; i < count; i++)
           {
               if ((node_symb+i)->symbol == byte)
               {
                   found = i;
                   break;
               }
           }
           if (found == -1)
           {
              
               (node_symb + count)->symbol = byte;
               (node_symb+count)->num_occurences = 1;
               (node_symb + count)->symbol= byte;
               ++count;
               found = -1;
           }
           else
           {
               ++(node_symb+i)->num_occurences;
               found = -1;
           }

       }
      
   }
   for (int i = 0; i < count; i++)
   {
   if((node_symb+i)->symbol == '\n')
   {
   printf("character newline found %d times \n", (node_symb+i)->num_occurences);
   }
   else if((node_symb+i)->symbol == 32)
   {
   printf("character space found %d times \n", (node_symb+i)->num_occurences);
   }
   else
       printf("character %c found %d times \n", (node_symb+i)->symbol, (node_symb+i)->num_occurences);
   }
}

=========================

//my input file

abcabda
bng da#@_
jh

//output

character a found 4 times                                                                                             

character b found 3 times                                                                                             

character c found 1 times                                                                                             

character d found 2 times                                                                                             

character newline found 2 times                                                                                       

character n found 1 times                                                                                             

character g found 1 times                                                                                             

character space found 2 times                                                                                         

character # found 1 times                                                                                             

character @ found 1 times                                                                                             

character _ found 1 times                                                                                             

character j found 1 times                                                                                             

character h found 1 times   

======================

//psl provide +ve rating , thanks