I am very new in C programming and have a question about it. I have the code bel

Question

I am very new in C programming and have a question about it. I have the code below and I need to rewrite it by dereferencing ptr (or some modification of ptr), NOT array indexing. I am asked for a solution with pointer arithmetic in the loop. Can anyone help please?

#include<stdio.h>
main () {
   int i=0, len;
   char s[ ] = "First Code!";
  
   len = strlen(s);
  
   for( i=0; i<len; i++)
       putc(s[i], stdout);
   printf(" length = %d ", i);
}

I did the following code but my teacher said that this is not what I am supposed to do when dereferencing a pointer (however this code is correct)

#include<stdio.h>

         #include <string.h>

         main () {

  int i=0, len;

  char s[ ] = "First Code!";

  char *ptr;

    ptr = s;

         len = strlen(ptr);

            for(i = 0; i < len; i++)

putc(ptr[i], stdout);

         printf(" length = %d ", i);}

Any help is appreciated.

Explanation / Answer

Dereferencing of pointers is be done with the help of dereference operator which is an unary operator denoted by, " * ". The operator when used with a pointer variable returns the l-value which is equivalent to the value at the pointer address. For e.g. Consider a pointer x as below:

char* x = "Hello"

Six bytes with the numerical values used to encode the letters 'H', 'e', 'l', 'l' , 'o' and a 0 byte to denote the end of the textual data, are stored somewhere in memory and the numerical address of that data is stored in x.

*x denotes the value 'H', similarly x[1] or *(x+1) denotes the value 'e' and so on.

So, we can write the above program simply as :

#include<stdio.h>

main () {

  char* ptr ="First Code!";

            while (*ptr!='')

           {

putc(*ptr++, stdout);

          }

    }

Or we can also take the string into an array and put it's value in the pointer and then dereference it to print the String.

#include<stdio.h>

main () {

            char s[ ] = "First Code!";

  char* ptr;

            ptr=s;

            while (*ptr!='')

           {

putc(*ptr++, stdout);

          }

    }

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