Error for c++ example - c++

Question

I want to input alphabet to binary code, and output the alphabet from generated binary code.
Example
1 --> a
01 --> b
001 --> c
0001 --> d
00001 --> e
000001 --> f
a => 1
b => 01
c => 001
d => 0001
e => 00001
-------------Encode.cpp--------------------
#include "Encode.h"
Encode::Encode()
{
}
Encode::~Encode()
{
}
void Encode::inputWord()
{
cout << "Input word: ";
cin.getline(word, 255);
return;
}// User input a word
char * Encode::getBuf(void)
{
return buffer;
}// return buffer to Decode::setBuf(char* buf)
void Encode::printEncResult()
{
int size = strlen(word);
int buffersize = 0;
cout << "Encoding result" << endl; // print similar binary
for (int i = 0; i < size; i++)
{
if (word[i] == 'z')
{
for (int j = 0; j < 25; j++)
{
cout<<buffer[buffersize++];
}
}
else
{
int len = (int)word[i] - (int)'a';
for (int j = 0; j < len; j++)
{
cout<<buffer[buffersize++];
}
cout << buffer[buffersize++];
}
}
}// output similar binary
int Encode::encodeWord(void)
{
int buffersize = 0;
int size = strlen(word);
for (int i = 0; i < size; i++)
{
if (word[i] == 'z')
{
for (int j = 0; j < 25; j++)
{
buffer[buffersize++] = '0';
}
}
else
{
int len = (int)word[i] - (int)'a';
for (int j = 0; j < len; j++)
{
buffer[buffersize++] = '0';
}
buffer[buffersize++] = '1';
}
}
return 0;
}// change word to similar binary
--------Decode.cpp-------------
#include "Decode.h"
Decode::Decode()
{
}
Decode::~Decode()
{
}
void Decode::setBuf(char * buf)
{
int i = 0;
int size = 0;
while (*(buf + i) == '1' || *(buf + i) == '0')
{
i++;
}
size = i;
for(int i = 0; i < size; i++)
{
buffer[i] = buf[i];
}
return;
}// set buffer from Encode::getBuf(void)
void Decode::printWord() // print similar binary
{
int i = 0;
int size = 0;
int check = 1;
while (check)
{
if (word[i] >= 'a' && (int)word[i] <= 'z')
{
i++;
size = i;
}
else
check = 0;
}
cout << "Decoding result" << endl;
for (int i = 0; i < size; i++)
{
if (word[i] >= 'a' && (int)word[i] <= 'z') // **this part is also strange** I can not shoten the code.
cout<<word[i];
}
cout << endl;
}
int Decode::decodebin(vector<char> buffer)
{
int buffersize = 0;
int check = 0;
int size = 0;
int i = 0;
char printval = 'a';
while (buffer[i] == '1' || buffer[i] == '0')
{
i++;
}
size = i;
for (int j = 0; j < size; j++) // nested loop does not work. I want save words in order
{
for (i = 0; i < size; i++)
{
if (buffer[i] == '0')
++printval;
else
{
word[j] = printval; // In this part, word[0] does not have any value.
printval = 'a';
}
}
}
return 0;
}
In this code, I want save values in order, but word[0] does not have any value. Moreover, If I input 'bb' then, 'bbbb' saved ins word array.

Answer 1

There are some problems and consideration you need to take care of:
as Fei Xiang said in the comments don't use magic numbers, use characters since you have a character array.
int printWord function you actually get the word and print the same word, there is no conversion as your problem statement. your didn't take buffer into account.
you are using some data validation to get your array size, this could end up a disaster(UB). you need to pass your array size to your function or use std::vector(Recommended).
in this statement if ((int)word[i] >= 97 || (int)word[i] <= 122) as I said don't use magic number and || should be change to && otherwise you end up in an infinity loop.
Anyway by keeping your approach(using array) and function signature here's what you can do :
int Decode::decodebin(void)
{
int buffersize = 0;
int check = 0;
int size = 0;
int i = 0;
char printval = 'a';
while(buffer[i] == '1' || buffer[i] == '0')
{
i++;
size = i;
}
for(int i = 0; i < size; i++)
{
if(buffer[i] == '0')
++printval;
else
{
cout << printval;
printval = 'a';
}
}
return 0;
}
void Decode::printWord()
{
int i = 0;
int size = 0;
int check = 1;
while(check)
{
if(word[i] >= 'a' && word[i] <= 'z')
{
i++;
size = i;
}
else
check = 0;
}
cout << "Decoding result" << endl;
for(int i = 0; i < size; i++)
{
int distance = word[i] - 'a';
for(int j = 0; j < distance; ++j)
cout << '0';
cout << '1';
}
cout << endl;
}
EDIT BASED ON OP REQUIREMENT IN COMMENTS:
using std::vector you can implement your needs like this :
#include <iostream>
#include <vector>
class Decode
{
public:
void decodebin(std::vector<char> buffer)
{
char printval = 'a';
for(unsigned int i = 0; i < buffer.size(); i++)
{
if(buffer[i] == '0')
++printval;
else
{
word.push_back(printval);
printval = 'a';
}
}
}
void printWord(void)
{
for(auto iter = word.begin(); iter != word.end(); ++iter)
std::cout << *iter;
std::cout << std::endl;
}
private:
std::vector<char> word;
};
int main()
{
Decode decoder;
std::vector<char> buffer = {'0', '1', '0', '0', '0', '0', '1', '0', '0', '0', '1'};
decoder.decodebin(buffer);
decoder.printWord();
return 0;
}
Here decodebin stores the given input into word member variable of Decode class. Then printWord function print word values on the screen.
std::vector has all the power of C-style array and it's nicer and easier to use. You can retrieve it's size whenever you want and you don't have to worry about the memory it's allocating.