QString::replace doesnt replace - c++

Question

Problem
I am trying to convert a string to a C string. In doing so, I need to replace " with \". I use the following code to do this:
QString Converter::plain2C(const QString &in) {
QString out;
// Split input in each line
QStringList list = in.split(QChar('\n'));
for (int i = 0; list.length() > i; i++) { // Go throught each line of the input
QString line = list[i]; // Thats the line
line.replace(QChar('\\'), QLatin1String("\\\\")); // replace \ with \\
line.replace(QChar('"'), QLatin1String("\\\"")); // replace " with \"
// For printf()
if(escapePercent)
line.replace(QChar('%'), QLatin1String("%%"));
// If option "Split output into multiple lines" is active add a " to the output
if (multiLine)
out.append(QChar('"'));
// append the line to the output
out.append(line);
// append a "\n" to the output because we are at the end of a line
if (list.length() -1 > i)
out.append(QLatin1String("\\n"));
// If option "Split output into multiple lines" is active add a " and \n to the output
if (multiLine) {
out.append(QChar('"'));
out.append(QChar('\n'));
}
}
if (!multiLine) {
out.prepend(QChar('"'));
out.append(QChar('"'));
}
return out;
}
However, " is still there without a \ before.
Information
Qt Version 5.15.3
C++17
Edit
The application is used to enter a normal string copied from the Internet and get as a result a string that can be copied into a C/C++ program.
More code
void Converter::run()
{
if (_from != From::NotSupportet &&
_to != To::toInvalid) {
QString out;
// More code obove and below
else if (_from == From::Plain) {
switch (_to) {
case To::toCString:
out = plain2C(_in);
break;
// Emits the ready string which is applied direct to a QPlainTextEdit
emit htmlReady(out);
}
}
Edit 2
Added more comments to the code

Answer 1

It works now. The problem was the line above:
line.replace(QChar('\'), QLatin1String("\\\\")); // replace \ with \\
The problem was that the comment ended with 2 \. That somehow disabled the next line or something like that.
Anyway, this is the working code:
QString Converter::plain2C(const QString &in) {
QString out;
// Split input in each line
QStringList list = in.split(QChar('\n'));
for (int i = 0; list.length() > i; i++) { // Go throught each line of the input
QString line = list[i]; // Thats the line
line.replace(QChar('\\'), QLatin1String("\\\\")); // replace "\" with "\\"
line.replace(QChar('"'), QLatin1String("\\\"")); // replace " with \"
// For printf()
if(escapePercent)
line.replace(QChar('%'), QLatin1String("%%"));
// If option "Split output into multiple lines" is active add a " to the output
if (multiLine)
out.append(QChar('"'));
// append the line to the output
out.append(line);
// append a "\n" to the output because we are at the end of a line
if (list.length() -1 > i)
out.append(QLatin1String("\\n"));
// If option "Split output into multiple lines" is active add a " and \n to the output
if (multiLine) {
out.append(QChar('"'));
out.append(QChar('\n'));
}
}
if (!multiLine) {
out.prepend(QChar('"'));
out.append(QChar('"'));
}
return out;
}