Hey forum, I'm very new to C++, and I need some help. I'm currently having trouble trying to write a Caesar cipher in C++. So far, I'm able to get it to read characters from a text file, and let it count the # each letter appears in an array. What I'm trying to do exactly is, find the most frequent letter, and then use that to find the shift. But before that, i want to display which letter that it was that was most frequent, and the number of times it was in the text.
#include <iostream>
#include <fstream>
#include <string>
#include <cmath>
#include <iomanip>
using namespace std;
//Globals
const int ARRAY_SIZE = 128;
const int E_LOC = 4;
int list[ARRAY_SIZE] = {0};
string reply;
ofstream outputFileName;
ifstream inputFile;
char ch;
//Prototypes
void characterCount(char ch, int list[]);
void calcShift( int& shift, int list[]);
void writeOutput(ifstream &in, ofstream &out, int shift);
int main() {
int shift = 0;
string inputFileName;
char ch;
//Input File Name
cout << "Input file name: ";
getline(cin, inputFileName);
// Open the input file.
inputFile.open(inputFileName.c_str());
// Check the file opened successfully.
if ( ! inputFile.is_open()) {
cout << "Unable to open input file." << endl;
cout << "Press enter to continue...";
getline(cin, reply);
exit(1);
}
//Open the output file.
cout << "Output file name: ";
getline(cin, inputFileName);
outputFileName.open(inputFileName.c_str());
// This section reads and echo's the file one character (byte) at a time.
while (inputFile.peek() != EOF)
{
inputFile.get(ch);
characterCount(ch, list);
}
calcShift(shift, list);
inputFile.clear();
inputFile.seekg(0);
inputFile.close();
inputFile.open(inputFileName.c_str());
cout << endl;
system("PAUSE");
return 0;
}
void characterCount(char ch, int list[])
{
if (ch >= 'a' && ch <= 'z')
{
int asciiCode = 0;
asciiCode = (static_cast<int>(ch));
list[asciiCode]++;
cout << ch;
}
}
void calcShift( int& shift, int list[])
{
int mostUsedLetter = list[0];
int mUsedIndex;
//Loop to search for greatest count and location (index) of greatest count.
for(int i = 0; i < ARRAY_SIZE; i++)
{
if(list[i] > mostUsedLetter)
{
mostUsedLetter = list[i];
mUsedIndex = i;
cout << endl << "The letter: " << static_cast<char>(mUsedIndex) << endl << " was shown " << mostUsedLetter << " times." << endl;
//shift = mUsedIndex - E_LOC;
}
}
}I just threw up a bunch of default headers first, and worked from there. This code isn't complete yet, but I'm going step by step and trying to fix my mistakes before i continue. The current problem I'm having at the moment is that when i execute the code, it displays all the characters normally, but at the point where i prompt it to display the most frequent letter, it displays the message twice. One for a and l. Why is it doing that? Feel free to flame me with feedback, I really need it. Advice on waht to do next would be nice too.
