Hi~
I've been stuck with this exercise for quite a few days. It's in a book I'm currently self-studying, C++ primer plus. It is as follow:
/*
Write a program that uses an array of char and a loop to read one word at a time until
the word done is entered. The program should then report the number of words entered
(not counting done). A sample run could look like this:
Enter words (to stop, type the word done):
anteater birthday category dumpster
envy finagle geometry done for sure
You entered a total of 7 words.
You should include the cstring header file and use the strcmp() function to make the
comparison test.
*/Since the exercise is in Chapter 5 - Loops and Relational Expressions, and Branching Statements and Logical Operators is Chapter 6, I can't use if statements here.
The following code is how I did it, but it has problems. The idea is to identify a word from the original array, place it in another array to compare with the "done" string, and increment the NumberOfWords variable accordingly.
There is no compile-time errors, but runtime errors there are >"< :
- I typed in "test string done", then pressed enter. The program halted, and VS2010 says: Unhandled exception at 0x011315f6 in C++PrimerPlusFrame.exe: 0xC0000005: Access violation reading location 0x00430000. and in the source code editor there is a yellow arrow poiting at line 46;
- I typed in "word test done", then pressed Enter, the program reported "The text has 2 words" correctly. But when I pressed "Enter" again, VS2010 says "Run-Time Check Failure #2 - Stack around the variable 'Analyzer' was corrupted.", and a yellow arrow points in the last line, the closing brace '}' of main(), of the source code.
Can anyone tell me what was going wrong here? And what do those two messages mean, access violation and stack corruption? And what is a stack, anyway? What do the two arrows point at? I am only a beginner, and I have only little experience with VS2010. Please, shed some light on me ^^"
Here is the source of the whole thing:
/*
Write a program that uses an array of char and a loop to read one word at a time until
the word done is entered. The program should then report the number of words entered
(not counting done). A sample run could look like this:
Enter words (to stop, type the word done):
anteater birthday category dumpster
envy finagle geometry done for sure
You entered a total of 7 words.
You should include the cstring header file and use the strcmp() function to make the
comparison test.
*/
#include <iostream>
#include <cstring>
int main()
{
using std::cin; using std::cout; using std::endl;
const unsigned int LIMIT = 1001; //The limit of analyzable words
char WordsToAnalyze[LIMIT] = {0}; //The array to store input text
char Analyzer[LIMIT] = {0}; //The temporary array used for analyzing
unsigned int NumberOfWords = 0; //The variable to keep track of number of words
//Intro
cout << "Welcome to WordCounter, char Edition!\n"
<< "Please enter the words, and use 'done' as the end-marker.\n"
<< "(maximum " << LIMIT - 1 << " characters.)" << endl;
cin.getline(WordsToAnalyze,LIMIT);
// <--- START WORD COUNTING --->
/*
- "done" as sentinel word.
- StringPointer: set at 0, serves as the marker of the processed character in WordsToAnalyze;
- LOOP: - Set CharPointer at 0, serves as the marker for Analyzer. Reset Analyzer.
- LOOP: Add character by character to Analyzer until a space in encountered;
- Increment NumberOfWords and StringPointer (to push it over the space);
- Check if Analyzer is "done";
- Repeat loop
- Decrement NumberOfWords (because "done" must not be counted).
*/
int StringPointer = 0; int CharPointer = 0;
do
{
CharPointer = 0; //Reset CharPointer and Analyzer
for ( WordsToAnalyze; WordsToAnalyze[StringPointer] != ' '; ++StringPointer)
{
Analyzer[CharPointer] = WordsToAnalyze[StringPointer];
++CharPointer;
}
++NumberOfWords;
++StringPointer;
Analyzer[CharPointer] = '\0';
} while ( strcmp(Analyzer,"done") != 0 );
NumberOfWords--;
//Analyzer[0] = '\0'; WordsToAnalyze[0] = '\0';
// <!--- END WORD COUNTING --->
//REPORT
cout << "That text has " << NumberOfWords << " words.";
cin.clear(); cin.get();
return 0;
}A little off-topic: A few days earlier I posted this problem in the C forum, and someone pointed out that this should be in the C++ forum instead, but I have no idea on how to 'move' a thread. The previous thread is here. Need a mod be contacted to do so?
