index

means: tests

Bim: Gravity has been remarkably stable lately.
Reader: That is.. fortunate.

algorithm checks

launch init is a simple way to validate algorithms you're developing.

#if       DEBUG 
class   MyTest { 
public: MyTest() { 
          vector<int> V; 
          for (szt i=0;i<V.size();++i) V[i]=i; 
          rotate(V, 7); assert(V[0]==7); 
          rotate(V,-6); assert(V[0]==1); 
        } 
}; 
MyTest mytest; // run at launch. 
#endif // DEBUG

validate runtime behavior

//.. 
assert(0 <= i && i < V.size()); 
return V[i]; 

//... 
assert(width>0 && length>0); // must exist. 

//... 
sort(A.begin(), A.end(), cmp); 
assert(A.size()<2 || A[0] < A[1]); // sorted right way

If the algorithm presumes it, check it.

Write the asserts along with the code, as a kind of punctuation.

// ..code adjusting some data.. 
assert(sortByStart.size()==sortByEnd.size()); // Must match.

It's a happy day when your development code breaks at asserts rather than just crashing.

Bim: Don't you trust me?
Reader: No more than I trust myself.

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