Calcmass | A molar mass calculator cli | Apps library

Within your class you define double calcmass(); which takes NO arguments and returns a double but later you try to declare it as double equip::calcmass(vector time) which takes a vector of doubles and returns a double. You should change the declaration within the class to double calcmass(vector time);

In C++ it is possible to overload functions, meaning two functions can have the same name but take different arguments. This means that you are referring to two different functions in your code.

Your code is not working because you defined a a class equip, but never created an instance of it in main, and then you try to read a file content into a member of class time. Also, your function calcmass in the class definition has no arguments, but later you declare it with argument of undetermined type time. Remove the argument of a function, it will see time anyway as they are both members of the same class.

You were missing a bunch of headers, and in the function declaration was missing the parameter presents in the function definition:

IMHO, OP suspected implicit vs. explicit conversion issues but that's not the reason. Instead, the stream I/O operators have to be investigated.

Elaborating the comment of S.M.:

49 is ASCII code of '1'. So look in the direction of unsigned char to understand why you get 49.

The std::stream operators work a little bit different for char, signed char, and unsigned char (operator<<(std::basic_ostream), operator>>(std::basic_istream)) than for the other integral types (std::basic_ostream::operator<<, std::basic_istream::operator>>).

That's for input as well as for output.

std::cout << (int)49; prints 49 but std::cout << (char)49; prints 1.

std::uint8_t is very likely a typedef unsigned char uint8_t;.
(SO: Implementation of fixed width integer types std::uint8_t and std::int8_t, C++)

Sample: