My variables are mixing values with each other ???? C++ - c++

Question

I have two string variables that are mixing each others letters after a certain point and I have no idea why.
string dna1 and dna2 is read in from a .txt file like this:
string opfile1(string& dnafile, string& dnaseq1); // function dec
string opfile2(string& dnafile, string& dnaseq2);
int main()
{
string dna1;
string dna2;
string seq1;
string seq2;
order1 = openSecondFile(dna1, seq1);
order2 = openThirdFile(dna2, seq2);
//function calls ^
string opfile1(string& dnafile, string& dnaseq1); // function dec
{
string PName;
string frag;
ifstream in_s;
in_s.open(dnafile.c_str());
if(in_s.fail()) //if file does not exist a fail message will appear
{
cout << "Unable to open input file " << song1File << endl;
exit(EXIT_FAILURE);
}
getline(in_s, frag, '|');
Name = frag.substr(1);
in_s >> dnaseq1;
in_s.clear();
return Name;
}
//func def.
The function opfile2 is the exact same except wherever you see a '1', I replaced it with a '2' to match its variables.
Now when I print these out in my main function they appear like this:
cout << dnaseq1 << endl;
cout << dnaseq2 << endl;
Output:
FDFDAFDAF
DFDAFDATZY
Which is correct! Now, when I try to print them using a for loop this happens:
int columns = dnaseq1Size + 1;
for(int i = 0; i < columns; ++i)
{
if(i == 0)
{
cout << setw(3) << "-" << " ";
}
else
{
cout << setw(3) << dnaseq2.at(i) << " ";
}
}
Output:
terminate called after throwing an instance of 'std::out_of_range'
what(): basic_string::at: __n (which is 9) >= this->size() (which is 9)
- D F D A F D A F Aborted (core dumped)
(it starts printing the other notes)
I have no idea what's happening, can anyone help?
EDIT: I figured out the issue and fixed it. I think the issue had something to do with the fact I was using arrays and a "size" so I switched to a 2D vector and used .size instead and the issue fixed it self.

Answer 1

It's clear enough. Your string has size 9, (FDFDAFDAF for example) but you try and print musicalnotes2.at(9). If your string has size 9 then only 0 to 8 are legal indexes
As said in the comments the suspicious part is when you write
int columns = song2Size + 1;
for(int i = 0; i < columns; ++i)
...
Why do you add one there? That seems to be the problem.

Answer 2

It sounds like looks like your're trying to print out each char from the musicalnotes variables
one way to be able to do it is to wrap it in a function (easier to reuse)
void printNotes(const string &musicalNotes) {
cout << setw(3) << "-" << " ";
for(int i = 0; i < musicalNotes.length(); ++i)
{
cout << setw(3) << musicalNotes.at(i) << " ";
}
cout << endl;
}
int main()
{
//... code up until you wish to print it
printNotes(musicalnotes1);
printNotes(musicalnotes2);
//... if you want something afterward
return 0;
}
Here we replace the int columns = song2Size + 1; with the length of the string, and prior to writing anything from there we write out the -
Example output would be:
- F D F D A F D A F
- D F D A F D A T Z Y
I assume that song2Size would be equal to the musicalnotes2.length(), if that's the case you do write over the strings length and therefor you get your out of bounds error. If it contains 9 chars then it would be at index 0,1...7,8 not to 9