Convention

Format Lambdas Like Blocks of Code.

int cutoff = 7;
std::find(foo.begin(),foo.end(),[&](const Foo &a,
const Foo &b) ->bool{
return a.blah<cutoff //use reference to get local var
});

Pay attention to the global object are initialized in right order. Because the order can be arrange in the same translation unit, but not between translation units, see effective c++ Item 47. So we don’t encourage you to use global object more.

Use _FILE_ and _LINE_ to capture the current file name and line number.

Use const replace #define to define global constants. Use static const to define class constant. (const means that it will not change, so I don’t need keep multi copy in multi objs, so I use static.)

Use Typedef to simplify Complicated Type expressions. It’s very useful in STL.

Typedef int(*CB)(int, const char*);//C++11 use function<>
CB callBack; //decare a functions pointer.

int sort(int, const char*){..}
callBack = sort; // & operator is optional here!!

Create a zero-valued enumerator to indicate an invalid or default state and make it the first one.

Declare all member variables private. Then use getter and setter functions to access them. Don’t return reference or pointer to private member varaibles through you public member functions.

Don’t use Multithread unless you really need it. Simultaneously respond to many events, e.g., 1)a web server. 2) interface and working thread. 3) take advantage of with multiple processor. Just remember, synchronization has high cost.

Use Early Exits to simplify code.

if(IsValid){   //bad style
   do something;
} else{
  return;
}

if(!IsValid)  // A better style is
  return;
..do something here.

Turn Predicate Loop into Predicate Function. It make you code clean and easy to understand.

for(v.begin....){   /bad style
  if(it->IsSth){
      flag = true; break;
  }
}
if(flag){...}

// A better style is define vHasSth() return bool.
if(vHasSth()){...}

Use Assert more in your project.

#include<cassert>
assert(index>=0 && "␣index␣is␣negative");
//output: Assertion failed: expression, file name, line number

Don’t evaluate end() every time through for loop

for(auto i = con.begin, e = con.end();i!=e; ++i){
...........
}

Use auto type deduction to make code more readable, and use auto & if you don’t need to copy the result. Below are highly recommended when yo use STL container.

for(const auto &val : Container) { read(val)};
for(auto val: Container) { change(val); save(val)};

//make sure Container contain pointer
for(auto *ptr: Container){ ptr->change();}
for(const auto *ptr: Container){ ptr->read();}

Common function interface: From here: you can see "const" only used in pointer or reference type. You should use more const in your projects.


	read	write

primitive (char, int, float)	pass value	pointer or reference

class, array, structure	const pointer or reference	pointer or reference

1.1.1.3 Convention