Converting std::string to Double with atof
When attempting to convert a std::string to a double using the atof function, some programmers encounter an issue where it consistently returns zero. To address this, the following revised code is recommended:
std::string num = "0.6"; double temp = ::atof(num.c_str());
The double colon (::) before atof specifies that we are calling the global function, which is necessary to resolve the issue.
Alternative Approaches
While atof is a valid option for string-to-double conversion, there are other approaches to consider:
Additional Considerations for Qt Projects
For Qt projects specifically, utilizing QString::toDouble() is recommended:
QString winOpacity("0.6"); double temp = winOpacity.toDouble();
For optimal performance when dealing with const char*, QByteArray::toDouble() should be preferred.
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