stl - How to read badly formatted input data in C++? -

i learning c++ , stuck on exercise. how read data not formatted correctly? example, given file need read data looks this:

1   z 2 1   xy 2 3   8000  e 1777  e 2001 

the first, second, , third lines make "module". there lot of data many modules input through keyboard. program has accept of user's input (until user decides type "q" quit) , read input , manipulate data. ideally, input formatted correctly example above, data have whitespace, tabs, carriage returns, or start data previous module, this:

2   r 5001  e 4777 1   z 2     1   xy 2 3   8000  e 1777 e 2001 

what best way read , manipulate input data bad formatting? in case want able extract 1 z 2, 1 xy 2, , 3 8000 e 1777 e 2001 , store in array or kind of stl container , able information later (like add, subtract, or multiply number based on whether there "a", "s", or "m" in front of number).

my program has able recognize z , xy variables , z = 2 , xy = 2.

you better answers if described logical purpose of parts of input better. i'm going guess each module starts count of how many variable name/numeric-value pairs follow, allows more structured approach reading , storing values. populate vector (array) of maps (binary trees) variable name value, convenient later lookups , processing.

std::vector<std::map<std::string, int>>> vars; int vars_in_module; while (cin >> vars_in_module) {     vars.emplace_back();  // add empty module vector     std::string identifier;     int value;     (int = 1; <= vars_in_module; ++i)         if (cin >> identifier >> value)             vars.back()[identifier] = value;  // add var module         else         {             std::cerr << "error parsing variable identifier & value\n";             exit(1);         } } 

the map re-sort lexicographically (using ascii order of left-most character, - if that's equal - 1 right etc.) rather preserve order in typed, may or may not matter depending on use put variables. maps fast search particular identifier later, use vector if cared input order.