Question

Assignment:

1. Read in info from text file (done)

2. Retrieve only parts of text file using substr method (done)

3. Store info into instance variables (need help)

Here is the code I am having trouble with:

string* lati;
lati = new string(data.substr(0, data.find_first_of(",")));

double* latDub;
latDub = new double(atof((char *)lati));

this->latitude = *latDub;

1. I need to store the latitude into the instance variable latitude.

2. The variable data is the read-in text file.

3. this->latitude is declared as a double.

I have tested and the variable lati is the correct value, but once I try to convert it into a double the value changes to 0 for some reason. I am specifically supposed to use the atof method when converting!

Answer 1

(char *)lati doesn’t do what you think it does. What you’re clearly trying to do there is get the char sequence associated with lati, but what you’re actually doing is just squeezing a string* into a char* which is all kinds of bad.

There’s a member function on std::string that will give you exactly what you want. You should review the documentation for string, and replace (char *)lati with a call to that function.