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Infinite Loop in Counting Function

packetpirate (388)
I'm writing a program for class. He wants us to count the number of instances of each lowercase and uppercase letter in a file, store the count of each letter in a struct member (array of structs 0-51 representing a-z and A-Z). But I've run into a problem.

In my count function, which is supposed to count each occurrence of these letters, it just goes into an infinite loop. I have no idea why. I made sure to type a sentence into the input file for testing purposes...

input.txt (what I type in) contains "This is a test of my letter counting program."

Here is the code:

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/*
	Project: CIS225 Chapter 11 - Programming Exercise 6
	Author: packetpirate
	Last Updated: 02/11/2011
*/

#include <iostream>
using std::cout;
using std::cin;
using std::endl;
#include <fstream>
using std::ofstream;
using std::ifstream;
#include <string>
using std::string;
#include <iomanip>
using std::setw;
using std::right;
using std::left;
using std::setfill;
#include <limits>

struct input_t {
	int charCount;
};

void openFile(ofstream& fout, ifstream& fin);
void count(ifstream& fin, input_t myInput[], int& low, int& upp);
void printResult(ofstream& fout, input_t myInput[], int& low, int& upp);

int main(int argc, char* argv[])
{
	input_t myInput[52];
	int low = 0;
	int upp = 0;

	ofstream fout;
	ifstream fin;

	openFile(fout, fin);
	count(fin, myInput, low, upp);

	fout.close();
	fin.close();

	cin.get();
	cout << endl << "Press <ENTER> to continue...";
	cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');

	return 0;
}

void openFile(ofstream& fout, ifstream& fin)
{
	string out_name;
	cout << "Output File: ";
	cin >> out_name;

	fout.open(out_name.c_str());
	if(!fout)
	{
		cout << "Invalid output file. Exiting...";
		return;
	}

	string in_name;
	cout << "Input File: ";
	cin >> in_name;

	fin.open(in_name.c_str());
	if(!fin)
	{
		cout << "Invalid input file. Exiting...";
		return;
	}
}

void count(ifstream& fin, input_t myInput[], int& low, int& upp)
{
	char loc;

	while(!fin.eof())
	{
		cin.get(loc);

		switch(loc)
		{
		case 'a':
			myInput[0].charCount += 1;
			low++;
			break;
		case 'b':
			myInput[1].charCount += 1;
			low++;
			break;
		case 'c':
			myInput[2].charCount += 1;
			low++;
			break;
		case 'd':
			myInput[3].charCount += 1;
			low++;
			break;
		case 'e':
			myInput[4].charCount += 1;
			low++;
			break;
		case 'f':
			myInput[5].charCount += 1;
			low++;
			break;
		case 'g':
			myInput[6].charCount += 1;
			low++;
			break;
		case 'h':
			myInput[7].charCount += 1;
			low++;
			break;
		case 'i':
			myInput[8].charCount += 1;
			low++;
			break;
		case 'j':
			myInput[9].charCount += 1;
			low++;
			break;
		case 'k':
			myInput[10].charCount += 1;
			low++;
			break;
		case 'l':
			myInput[11].charCount += 1;
			low++;
			break;
		case 'm':
			myInput[12].charCount += 1;
			low++;
			break;
		case 'n':
			myInput[13].charCount += 1;
			low++;
			break;
		case 'o':
			myInput[14].charCount += 1;
			low++;
			break;
		case 'p':
			myInput[15].charCount += 1;
			low++;
			break;
		case 'q':
			myInput[16].charCount += 1;
			low++;
			break;
		case 'r':
			myInput[17].charCount += 1;
			low++;
			break;
		case 's':
			myInput[18].charCount += 1;
			low++;
			break;
		case 't':
			myInput[19].charCount += 1;
			low++;
			break;
		case 'u':
			myInput[20].charCount += 1;
			low++;
			break;
		case 'v':
			myInput[21].charCount += 1;
			low++;
			break;
		case 'w':
			myInput[22].charCount += 1;
			low++;
			break;
		case 'x':
			myInput[23].charCount += 1;
			low++;
			break;
		case 'y':
			myInput[24].charCount += 1;
			low++;
			break;
		case 'z':
			myInput[25].charCount += 1;
			low++;
			break;
		case 'A':
			myInput[26].charCount += 1;
			upp++;
			break;
		case 'B':
			myInput[27].charCount += 1;
			upp++;
			break;
		case 'C':
			myInput[28].charCount += 1;
			upp++;
			break;
		case 'D':
			myInput[29].charCount += 1;
			upp++;
			break;
		case 'E':
			myInput[30].charCount += 1;
			upp++;
			break;
		case 'F':
			myInput[31].charCount += 1;
			upp++;
			break;
		case 'G':
			myInput[32].charCount += 1;
			upp++;
			break;
		case 'H':
			myInput[33].charCount += 1;
			upp++;
			break;
		case 'I':
			myInput[34].charCount += 1;
			upp++;
			break;
		case 'J':
			myInput[35].charCount += 1;
			upp++;
			break;
		case 'K':
			myInput[36].charCount += 1;
			upp++;
			break;
		case 'L':
			myInput[37].charCount += 1;
			upp++;
			break;
		case 'M':
			myInput[38].charCount += 1;
			upp++;
			break;
		case 'N':
			myInput[39].charCount += 1;
			upp++;
			break;
		case 'O':
			myInput[40].charCount += 1;
			upp++;
			break;
		case 'P':
			myInput[41].charCount += 1;
			upp++;
			break;
		case 'Q':
			myInput[42].charCount += 1;
			upp++;
			break;
		case 'R':
			myInput[43].charCount += 1;
			upp++;
			break;
		case 'S':
			myInput[44].charCount += 1;
			upp++;
			break;
		case 'T':
			myInput[45].charCount += 1;
			upp++;
			break;
		case 'U':
			myInput[46].charCount += 1;
			upp++;
			break;
		case 'V':
			myInput[47].charCount += 1;
			upp++;
			break;
		case 'W':
			myInput[48].charCount += 1;
			upp++;
			break;
		case 'X':
			myInput[49].charCount += 1;
			upp++;
			break;
		case 'Y':
			myInput[50].charCount += 1;
			upp++;
			break;
		case 'Z':
			myInput[51].charCount += 1;
			upp++;
			break;
		default:
			break;
		}
	}
}

void printResult(ofstream& fout, input_t myInput[], int low, int upp)
{

}


So does anyone know what's causing this infinite loop?
ultifinitus (1446)
Yes

Your problem is you're never actually incrementing your file's position pointer, in count()

At first glance, i'd say change cin.get(blahblah) to fin.get(blahblah)
packetpirate (388)
<facepalm>

Thanks...
packetpirate (388)
Ok, new problem...

Now I'm having trouble with my print function...

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/*
	Project: CIS225 Chapter 11 - Programming Exercise 6
	Author: packetpirate
	Last Updated: 02/11/2011
*/

#include <iostream>
using std::cout;
using std::cin;
using std::endl;
#include <fstream>
using std::ofstream;
using std::ifstream;
#include <string>
using std::string;
#include <iomanip>
using std::setw;
using std::right;
using std::left;
using std::setfill;
#include <limits>

struct input_t {
	char x;
	int charCount;
};

void openFile(ofstream& fout, ifstream& fin);
void count(ifstream& fin, input_t myInput[], int& low, int& upp);
void printResult(ofstream& fout, input_t myInput[], int& low, int& upp);

int main(int argc, char* argv[])
{
	input_t myInput[52];
	char letters[] = {'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z',
	'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z'};

	for(int i = 0;i < 52;i++)
	{
		myInput[i].x = letters[i];
	}

	int low = 0;
	int upp = 0;

	ofstream fout;
	ifstream fin;

	openFile(fout, fin);
	count(fin, myInput, low, upp);
	printResult(fout, myInput, low, upp);

	fout.close();
	fin.close();

	cin.get();
	cout << endl << "Press <ENTER> to continue...";
	cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');

	return 0;
}

void openFile(ofstream& fout, ifstream& fin)
{
	string out_name;
	cout << "Output File: ";
	cin >> out_name;

	fout.open(out_name.c_str());
	if(!fout)
	{
		cout << "Invalid output file. Exiting...";
		return;
	}

	string in_name;
	cout << "Input File: ";
	cin >> in_name;

	fin.open(in_name.c_str());
	if(!fin)
	{
		cout << "Invalid input file. Exiting...";
		return;
	}
}

void count(ifstream& fin, input_t myInput[], int& low, int& upp)
{
	char loc;

	while(fin)
	{
		fin.get(loc);

		switch(loc)
		{
		case 'a':
			myInput[0].charCount += 1;
			low++;
			break;
		case 'b':
			myInput[1].charCount += 1;
			low++;
			break;
		case 'c':
			myInput[2].charCount += 1;
			low++;
			break;
		case 'd':
			myInput[3].charCount += 1;
			low++;
			break;
		case 'e':
			myInput[4].charCount += 1;
			low++;
			break;
		case 'f':
			myInput[5].charCount += 1;
			low++;
			break;
		case 'g':
			myInput[6].charCount += 1;
			low++;
			break;
		case 'h':
			myInput[7].charCount += 1;
			low++;
			break;
		case 'i':
			myInput[8].charCount += 1;
			low++;
			break;
		case 'j':
			myInput[9].charCount += 1;
			low++;
			break;
		case 'k':
			myInput[10].charCount += 1;
			low++;
			break;
		case 'l':
			myInput[11].charCount += 1;
			low++;
			break;
		case 'm':
			myInput[12].charCount += 1;
			low++;
			break;
		case 'n':
			myInput[13].charCount += 1;
			low++;
			break;
		case 'o':
			myInput[14].charCount += 1;
			low++;
			break;
		case 'p':
			myInput[15].charCount += 1;
			low++;
			break;
		case 'q':
			myInput[16].charCount += 1;
			low++;
			break;
		case 'r':
			myInput[17].charCount += 1;
			low++;
			break;
		case 's':
			myInput[18].charCount += 1;
			low++;
			break;
		case 't':
			myInput[19].charCount += 1;
			low++;
			break;
		case 'u':
			myInput[20].charCount += 1;
			low++;
			break;
		case 'v':
			myInput[21].charCount += 1;
			low++;
			break;
		case 'w':
			myInput[22].charCount += 1;
			low++;
			break;
		case 'x':
			myInput[23].charCount += 1;
			low++;
			break;
		case 'y':
			myInput[24].charCount += 1;
			low++;
			break;
		case 'z':
			myInput[25].charCount += 1;
			low++;
			break;
		case 'A':
			myInput[26].charCount += 1;
			upp++;
			break;
		case 'B':
			myInput[27].charCount += 1;
			upp++;
			break;
		case 'C':
			myInput[28].charCount += 1;
			upp++;
			break;
		case 'D':
			myInput[29].charCount += 1;
			upp++;
			break;
		case 'E':
			myInput[30].charCount += 1;
			upp++;
			break;
		case 'F':
			myInput[31].charCount += 1;
			upp++;
			break;
		case 'G':
			myInput[32].charCount += 1;
			upp++;
			break;
		case 'H':
			myInput[33].charCount += 1;
			upp++;
			break;
		case 'I':
			myInput[34].charCount += 1;
			upp++;
			break;
		case 'J':
			myInput[35].charCount += 1;
			upp++;
			break;
		case 'K':
			myInput[36].charCount += 1;
			upp++;
			break;
		case 'L':
			myInput[37].charCount += 1;
			upp++;
			break;
		case 'M':
			myInput[38].charCount += 1;
			upp++;
			break;
		case 'N':
			myInput[39].charCount += 1;
			upp++;
			break;
		case 'O':
			myInput[40].charCount += 1;
			upp++;
			break;
		case 'P':
			myInput[41].charCount += 1;
			upp++;
			break;
		case 'Q':
			myInput[42].charCount += 1;
			upp++;
			break;
		case 'R':
			myInput[43].charCount += 1;
			upp++;
			break;
		case 'S':
			myInput[44].charCount += 1;
			upp++;
			break;
		case 'T':
			myInput[45].charCount += 1;
			upp++;
			break;
		case 'U':
			myInput[46].charCount += 1;
			upp++;
			break;
		case 'V':
			myInput[47].charCount += 1;
			upp++;
			break;
		case 'W':
			myInput[48].charCount += 1;
			upp++;
			break;
		case 'X':
			myInput[49].charCount += 1;
			upp++;
			break;
		case 'Y':
			myInput[50].charCount += 1;
			upp++;
			break;
		case 'Z':
			myInput[51].charCount += 1;
			upp++;
			break;
		default:
			break;
		}
	}
}

void printResult(ofstream& fout, input_t myInput[], int& low, int& upp)
{
	for(int i = 0;i < 52;i++)
	{
		fout << setfill(' ');
		fout << left << setw(5) << myInput[i].x << right << setw(5) << myInput[i].charCount << endl;
	}
}


I'm getting the following output.


a -858993458
b -858993460
c -858993459
d -858993460
e -858993457
f -858993459
g -858993458
h -858993459
i -858993457
j -858993460
k -858993460
l -858993459
m -858993458
n -858993458
o -858993457
p -858993459
q -858993460
r -858993457
s -858993457
t -858993455
u -858993459
v -858993460
w -858993460
x -858993460
y -858993459
z -858993460
A -858993460
B -858993460
C -858993460
D -858993460
E -858993460
F -858993460
G -858993460
H -858993460
I -858993460
J -858993460
K -858993460
L -858993460
M -858993460
N -858993460
O -858993460
P -858993460
Q -858993460
R -858993460
S -858993460
T -858993459
U -858993460
V -858993460
W -858993460
X -858993460
Y -858993460
Z -858993460


Why is it giving me those weird numbers?
Last edited on
firedraco (6243)
You never initialize the count member variable of your type so they are garbage.
Ultima (20)
interesting cases.. why not convert ur letters into decimal values using ascii table like...

'A to Z' = 65 to 90
'a to z' = 97 to 122

then offset it accordingly?
packetpirate (388)
Ultima, someone at ProgrammingForums.org already suggested that. I'm not counting instances of letters in a string. I'm counting them from a file.
I'd like to hear alternative suggestions, though.
ne555 (10692)
Don't be so narrow-minded
I'm not counting instances of letters in a string. I'm counting them from a file.
You are counting letters, period.
Besides, if you know how to count letters in a string then you just pass all the content of your file to a string and count the letters.
Do you see the beauty of modularity?
packetpirate (388)
Except that the assignment tells me not to do that... it tells me to store the individual characters in an array of structs.
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