Question

In C: I need help up implementing this function that takes a line and breaks it into words without using sscanf

/*

This function takes a line and breaks it into words.

The orginal line is in the char array str, the first word

will go into the char array c, the second into p1, and the

the third into p2. If there are no words, the corresponding

char arrays are empty. At the end, n contains the number of

words read.

*/

void breakUp(char *str, char *c, char *p1, char *p2, int *n)

{

c[0] = p1[0] = p2[0] = '\0';

  

/* YOU CANNOT USE THE FOLLOWING! */

// cannot use sscanf: *n = sscanf(str,"%s %s %s %*s", c, p1, p2);

// break up manually

  

}

Answer 1

Please find properly commented and working code below :
------------------------------------------------------------------

#include<stdio.h>
#include<string.h>
#include<stdlib.h>

/*
This function takes a line and breaks it into words.
The orginal line is in the char array str, the first word
will go into the char array c, the second into p1, and the
the third into p2. If there are no words, the corresponding
char arrays are empty. At the end, n contains the number of
words read.
*/
void breakUp(char *str, char *c, char *p1, char *p2, int *n)
{
   c[0] = p1[0] = p2[0] = '\0';
   /* YOU CANNOT USE THE FOLLOWING! */
   // cannot use sscanf: *n = sscanf(str,"%s %s %s %*s", c, p1, p2);
   // break up manually
   char * ptr = str;           //Temporary pointer for traversing string
   int count = 0;               //Temporary counter
   *n = 0;                      

   if (*ptr == '\0')           //If string is empty, return
       return;
  
   while(*ptr != ' ' && *ptr != '\0'){       //Read the first word and put in c[]
       *(c + count) = *(ptr);
       count++;
       ptr++;
   }

   *n = 1;                                   //Update the n and reset count variables
   c[count] = '\0';
   if (*ptr == '\0')                      
       return;
   else
       ptr++;
   count = 0;

   while(*ptr != ' ' && *ptr != '\0'){       //Read the first word and put in c[]
       *(p1 + count) = *(ptr);
       count++;
       ptr++;
   }

   *n = 2;                                   //Update the n and reset count variables
   p1[count] = '\0';
   if (*ptr == '\0')
       return;
   else
       ptr++;
   count = 0;

   while(*ptr != ' ' && *ptr != '\0'){
       *(p2 + count) = *(ptr);
       count++;
       ptr++;
   }

   *n = 3;
   p2[count] = '\0';

  
   return;
}

int main()
{
   char str[100];
   printf("Enter the string to be split : \n");
   scanf("%[^\t\n]s", str);
   char c[100], p1[100],p2[100];
   int n;
   breakUp(str, c, p1,p2,&n);
   printf("n = %d\n", n);
   printf("First word is : %s\n", c);
   if(n>=2)
       printf("Second word is : %s\n", p1);
   if(n>2)
       printf("Third word is : %s\n", p2);
}

------------------------------------------------------------------

Please find the screenshot for working code :