Question

Hi! I wrote two function to get count cluster of char in a string , charFreq(), and an other one which iterate through a vector line by line looking for last element on each line, last(). The problem is, after appending all chars in a string and try to count clusters of values in that string, I get seg fault. I feel like my logic behind is ok, but I am not sure what I did wrong. Can someone help and tell me where are my errors. Also, all computation are done on txt file.

-----------------------------------------------------------------------------:c++ program

#include <iostream>

#include <string>

#include <vector>

#include <algorithm>

#include <fstream>

using namespace std;

//func to check frequency of a char in a string

void charFreq(string& Mystring){

int w = 1;

vector<int> count; //store all freq int into a vector

for(int i = 0; i <= Mystring.length(); i++){

if(Mystring.at(i)== Mystring.at(i+1))//if two adjacent value are the same increment my w: aaa = 3a

{

w++;

count[i]=w;

}

}

//print out all int charFreq.

for(int x = 0; x < count.size()-1; x++){

cout << count[x]<<" ";

}

}

void printArray(vector<string> array) {

for (int i = 0; i < array.size() - 1; ++i)

cout << array[i] << endl;

}

//iterate through vector looking for last char and append all chars into one string

string last(vector<string>& line){

char w;

string x;

string y = " ";

for(int i = 0; line.size(); i++){

w = x.at(x.length()-1);//find last char in a string

y += w;//append my char to a string

}

return y;//return entire string of appended chars

}

int main(int argc, char *argv[])

{

string i;

string input_line;

vector<string> value;

ifstream infile("Freq.txt");

if (infile.is_open())

{

while (getline(infile, input_line))

{

for (int i = 0; i < input_line.size(); i++)

{

value.push_back(input_line);//push individual input_line into vector value

charFreq(input_line);

printArray(value);

last(value);

}

}

infile.close();

}

return 0;

}

------------------------------------------------------------------------------------------------Freq.txt file

there!Hi

!Hi there

Adios

Hi there!

diosA

e!Hi ther

ere!Hi th

here!Hi t

i there!H

iosAd

osAdi

re!Hi the

sAdio

---------------------------------output

1i 1e 1s 1!.........................1o

Answer 1

/*
you did wrong in for loop where "i=Mystring.length()"
when i=Mystring.length() and you write Mystring.at(i+1) which is illegal memory access/
prompt to segmentation fault.
*/

#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <fstream>

using namespace std;

//func to check frequency of a char in a string

void charFreq(vector<char> & Mystring)
{
int hash[128]={};
//store all freq int into a vector

for(int i = 0; i <Mystring.size(); i++)
{
hash[Mystring.at(i)]++;
for(int j=i+1;j<Mystring.size();j++)
{
if(Mystring.at(i)==Mystring.at(j))
{
hash[Mystring.at(i)]++;
}
}
}
for(int i=0;i<128;i++)
{
if(hash[i]>=1)
cout<<(char)i<<" "<<hash[i]<<endl;
}
}

void printArray(vector<char> &array) {

for (auto i = array.begin(); i != array.end(); ++i)
cout << *i ;
cout<<endl;
}

char last(string &line){

if(line.length()>0)
return line.at(line.length()-1);//return entire string of appended chars
return '~';

}

int main(int argc, char *argv[])
{
string i;
string input_line;
vector<char> value;
ifstream infile("Freq.txt");
if (infile.is_open())

{

while (infile)

{

getline(infile, input_line);
if(input_line.length()>0)
value.push_back(last(input_line));//push individual input_line into vector value

}
printArray(value);
charFreq(value);
infile.close();

}
return 0;
}