new to C...need to eliminate whitespace

hello i am new to the programming world and was wondering if anyone could help me out with a problem i am having.....i need to accept keyboard input, and reproduce it after eliminating whitespace unless in "string literal"....so far i am able to print the input but im not quite sure how im supposed to delete the whitespace....here is what i have so far...

Code:

---


#include <stdio.h>

int main()
{
  int c;
 
  printf("This program eliminates whitespace from an input stream,\n");
  printf("except from within string literals in double quotes.\n");
  printf("\n");
  printf("Type characters, and enter EOF after <enter> to finish:\n");
 
  while ((c = getchar()) != EOF) {
      putchar(c);
}
  system("pause");
 
  return 0;
}

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i dont expect anyone to do this for me....but i have a textbook and notes and i just dont understand how to get this done....if anyone could give me any hints i would appreciate it. thanks

Add one bool variable, in_string_literal. Initialize it to false, and toggle it whenever you see a ".

In the loop, if c is whitespace and in_string_literal is false, don't print it.

im sorry but i dont understand what you are saying...i have only taken 3 classes so far in INTRO to C programming....whats is a bool? and how do i toggle? and how do i say string literal is false? im sorry im probably asking really stupid questions but i just dont understand

anyone??

Wow you are given this assignment after 3 classes? What is your teacher smoking :).

That aside,

Code:

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bool in_string_literal = false;

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a bool (http://en.wikipedia.org/wiki/Boolean_datatype) is a type (like char or int) that can only have 2 states, true and false.

Toggle means set it to true if it's false, and set it to false if it's true.
The easiest way to do that is with an exclusive-or

Code:

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in_string_literal ^= 1;

---

But I am guessing you haven't learned that, yet.
http://www.cprogramming.com/tutorial...operators.html
(it's probably a little too advanced for you at this stage, don't worry about it)

Just use an if, then

Code:

---

if (in_string_literal) {
    in_string_literal = false;
} else {
    in_string_literal = true;
}

---

Quote:

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how do i say string literal is false?

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Code:

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if (in_string_literal == false)

---

or

Code:

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if (!in_string_literal)

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this is pure C
why is it on the C++ board?

Quote:

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Originally Posted by vart

this is pure C
why is it on the C++ board?

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Indeed, so I have moved it to the C programming forum.

Just curious if you also need to figure out how to separate a string literal from a line with an embedded double-quote as in.
=> this is a line with an " embedded double-quote
=> "this is a string literal"