(C++) MakeSquare

 

Math code snippet to square all elements in a container (that is: to multiply each element with itself).

 

There are multiple ways to implement MakeSquare:

1. Using an algorithm (preferred [1][2])
2. Using a for-loop

 

 

 

 

 

MakeSquare using an algorithm

 

This is the anwer of exercise #9: No for-loops #14.

 

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#include <algorithm> #include <functional> #include <vector> template <class T> struct Square : public std::unary_function<T,T> {   const T operator()(const T& x) const { return x*x; } }; void MakeSquare(std::vector<int>& v) {   std::transform(v.begin(),v.end(),v.begin(),Square<int>()); }

 

 

 

 

 

MakeSquare using a for-loop

 

Prefer algorithms over loops [1][2].

 

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#include <vector> void MakeSquare(std::vector<int>& v) {   const int sz = v.size();   for (int i=0; i!=sz; ++i)   {     v[i]*=v[i];   } }

 

 

 

 

 

References

 

1. Bjarne Stroustrup. The C++ Programming Language (3rd edition). ISBN: 0-201-88954-4. Chapter 18.12.1 : 'Prefer algorithms over loops'
2. Herb Sutter and Andrei Alexandrescu. C++ coding standards: 101 rules, guidelines, and best practices. ISBN: 0-32-111358-6. Chapter 84: 'Prefer algorithm calls to handwritten loops.'