c++ problem with character manipulation

Hi. I am having a problem with an assignment I am working on. I am suppose to read in two sentences from a user, read in each character one at a time, and check to see if the last three letters of the last word in each sentence are the same. Each sentence ends with a newline character. I currently just have the user entering one sentence, until I can get the first one working! I am not suppose to use strings or arrays, just single characters.

Attached is my source code. I have a loop to read in the characters one at a time, but am not sure how to 'extract' the last three letters out of each sentence (because I don't have a variable assigned to each individual letter, not knowing how long of a sentence the user is entering). Also, my program feels big and bulky with lots of variables. Is there a easier way?

Thanks in advance!

[CODE]

Code:

#include <iostream.h>
using namespace std;

// assign variables
int main ()
{
char ch;
char ch1;
char ch2;
char ch3;
char ch4;
char ch5;
char ch6;
char ch7;
char ch8;
char ch9;
char ch10;
char ch11;
char ch12;
char ch13;
char ch14;
char ch15;
int i = 0;
//get line 1 of poem from user
cout << "Please enter a sentence followed by return" <<endl;
cin.get(ch);

// loop that will loop through and read in
// each character one at a time
//echoing back just for testing.

while (ch != '\n'){

        if (i == 15)
{       ch = ch1;
        i = 0;
}
        if (ch == '\n')
        continue;
        continue;
        ch1 = ch;
        cout << ch1 << endl;
        i++;
        cin.get(ch);
         if (ch == '\n')
        continue;
        ch2 = ch;
        cout << ch2 <<endl;
        i++;
        cin.get(ch);
         if (ch == '\n')
        continue;
        ch3 = ch; 
        cout << ch3 <<endl;
        i++;  
        cin.get(ch);
         if (ch == '\n')
        continue;
        ch4 = ch;
        cout << ch4 <<endl;
        i++;   
        cin.get(ch);
         if (ch == '\n')
        continue;
        ch5 = ch;
        cout << ch5 <<endl;
        i++;   
       cin.get(ch);
 if (ch == '\n')
        continue;
        ch6 = ch;
        cout << ch6 <<endl;
        i++;   
       cin.get(ch);
 if (ch == '\n')
        continue;
        ch7 = ch;
        cout << ch7 <<endl;
        i++;   
        cin.get(ch);
 if (ch == '\n')
        continue;
        ch8 = ch;
        cout << ch8<<endl;
        i++;   
        cin.get(ch);
 if (ch == '\n')
        continue;
        ch9 = ch;
        cout << ch9<<endl;
        i++;   
        cin.get(ch);
         if (ch == '\n')
        continue;
        ch10 = ch;
        cout <<ch10<<endl;
        i++;   
       cin.get(ch);
 if (ch == '\n')
        continue;
        ch11 = ch;
        cout <<ch11<<endl;
        i++;   
        cin.get(ch);
 if (ch == '\n')
       continue;
        ch12 = ch;
        cout <<ch12<<endl;
        i++;   
        cin.get(ch);
 if (ch == '\n')
        continue;
        ch13 = ch;
        cout << ch13<<endl;
        i++;   
        cin.get(ch);
 if (ch == '\n')
        continue;
        ch14 = ch;
        cout <<ch14<<endl;
        i++;   
        cin.get(ch);
 if (ch == '\n')
        continue;
        ch15 = ch;   
        cout <<ch15<<endl;
        i++;
        }




if (ch == '\n')
//number of loops it went through
cout<< i;

return 0;
}

Code:

bool validate(void)
{
 int count = 1;
 char ch, last_char = 0;
 
   while(1)
  {
   cin.get(ch);

      if(ch == '\n')
     {
         if(count == 3)
          return true;
         else
          return false;
     }
      else if(ch == last_char)
       ++count;
      else
       count = 1;

   last_char = ch;
  }
 return false;
}

int main()
{
 bool condition1 = validate();
 bool condition2 = validate();

 cout << "The input was ";

 if(condition1 && condition2)
  cout << "valid";
 else cout << "invalid";

 cin.get();
}

Here is a working piece of code for your assignment. Fully done, i was bored so don't expect it to be done often....

Code:

#include <iostream>
using namespace std;

int main()
{
	// Variables s1 = Sentence 1, s2 = Sentence 2, ch1 = Character 1, etc.....
	char s1ch1 = '\0';
	char s1ch2 = '\0';
	char s1ch3 = '\0';

	char s2ch1 = '\0';
	char s2ch2 = '\0';
	char s2ch3 = '\0';

	// Get the first sentence
	cout << "Please enter your first sentence: ";

	s1ch1 = cin.get();
	s1ch2 = cin.get();
	s1ch3 = cin.get();

	while(cin.peek() != '\n')
	{
		s1ch1 = s1ch2;
		s1ch2 = s1ch3;
		s1ch3 = cin.get();
	}

	cin.get(); // Gets the last new line from the buffer

	cout << "Please enter your second sentence: ";

	s2ch1 = cin.get();	// Gets first letter in sentence
	s2ch2 = cin.get();  // Gets second letter in sentence
	s2ch3 = cin.get();  // Gets third letter in sentence

	while(cin.peek() != '\n')
	{
		s2ch1 = s2ch2;
		s2ch2 = s2ch3;
		s2ch3 = cin.get();
	}

                cin.get(); // Gets the last new line from the buffer

	// Checks if the three characters from each sentence are the same
	if((s1ch1 == s2ch1) && (s1ch2 == s2ch2) && (s1ch3 == s2ch3))
		cout << "Last Three latters where the same." << endl;
	else
		cout << "Last Three letters where not the same." << endl;
	
	return 0;
}

if you don't know how cin.peek() works you might wanna consider replacing:

Code:

while(cin.peek() != '\n')
{
	s1ch1 = s1ch2;
	s1ch2 = s1ch3;
	s1ch3 = cin.get();
}

cin.get(); // Gets the last new line from the buffer

and the equivilant block for the second sentence with something like:

Code:

char temp = cin.get();

while(temp != '\n')
{
	s1ch1 = s1ch2;
	s1ch2 = s1ch3;
	s1ch3 = temp;

	temp = cin.get();
}

in the basis what this program does is it gets the first three letter from the sentence. Then until it finds a '\n' it will set the first letter equal to the first, the second equal to the third and the third equal to one newly gotten from the buffer.

Thanks, that helped out a lot. I am new to C++ and because my classes are so large, there isn't much opportunity for any one on one interaction with the instructor. I wouldn't have thought of shifting the variables, but that makes the whole program much simplier.

Thanks for you help and also for explaining why you did what you did!

scrapper777