Occasional unhandled exception with atoi(string.c_str()) Updated - c++

Question

UPDATE
I thought stoi(string) solved it, but it only worked for a little while.
I have added the code for splitString and decrypt below.
I occasionally get unhandled exceptions with atoi() using the supposable same value.
My code looks like this:
ifstream myfile ("Save.sav");
string line = "";
if (myfile.is_open())
{
while ( myfile.good() )
{
getline (myfile,line);
}
myfile.close();
line = StaticFunctions::decrypt(line);
}
vector<string> splitString = StaticFunctions::splitString(line, 's');
return atoi(splitString[0].c_str());
So what it does is reading a savefile, then it decrypts it and then it splits the string by every 's'. When I'm debugging, the savefile is always the same and the first value is 3.
This work sometimes, maybe every 10 attempt. So every 9 out of 10 attempts I get unhandled exception at ... at memory location.
Monitoring the converted value shows it always returns 3 and then the application doesn't crash until I start the game which is a bit further in the code.
If I remove the atoi and just return 3 the application works fine.
I've tried strtod but it didn't help.
Thanks,
Markus
SplitString code:
vector<string> StaticFunctions::splitString(string str, char splitByThis)
{
vector<string> tempVector;
unsigned int pos = str.find(splitByThis);
unsigned int initialPos = 0;
// Decompose statement
while( pos != std::string::npos ) {
tempVector.push_back(str.substr( initialPos, pos - initialPos + 1 ) );
initialPos = pos + 1;
pos = str.find(splitByThis, initialPos );
}
// Add the last one
tempVector.push_back(str.substr(initialPos, std::min(pos, str.size()) - initialPos + 1));
return tempVector;
}
Decrypt code (very simple):
string StaticFunctions::decrypt(string decryptThis)
{
for(int x = 0; x < decryptThis.length(); x++)
{
switch(decryptThis[x])
{
case '*':
{
decryptThis[x] = '0';
break;
}
case '?':
{
decryptThis[x] = '1';
break;
}
case '!':
{
decryptThis[x] = '2';
break;
}
case '=':
{
decryptThis[x] = '3';
break;
}
case '#':
{
decryptThis[x] = '4';
break;
}
case '^':
{
decryptThis[x] = '5';
break;
}
case '%':
{
decryptThis[x] = '6';
break;
}
case '+':
{
decryptThis[x] = '7';
break;
}
case '-':
{
decryptThis[x] = '8';
break;
}
case '"':
{
decryptThis[x] = '9';
break;
}
}
}
return decryptThis;
}

Answer 1

Try use strtol instead
strtol (splitString[0].c_str(),NULL,10);

Answer 2

stoi(string) instead of atoi(string.c_str()) solved it.
UPDATE:
It did not solve it.