Generalized Operations

Generalized Operations
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Chapter 12. + Numerics + +

Generalized Operations

There are four generalized functions in the <numeric> header + that follow the same conventions as those in <algorithm>. Each + of them is overloaded: one signature for common default operations, + and a second for fully general operations. Their names are + self-explanatory to anyone who works with numerics on a regular basis: +

accumulate
inner_product
chapterial_sum
adjacent_difference

Here is a simple example of the two forms of accumulate. +

+   int   ar[50];
+   int   someval = somefunction();
+
+   // ...initialize members of ar to something...
+
+   int  sum       = std::accumulate(ar,ar+50,0);
+   int  sum_stuff = std::accumulate(ar,ar+50,someval);
+   int  product   = std::accumulate(ar,ar+50,1,std::multiplies<int>());
+

The first call adds all the members of the array, using zero as an + initial value for sum. The second does the same, but uses + someval as the starting value (thus, sum_stuff == sum + + someval). The final call uses the second of the two signatures, + and multiplies all the members of the array; here we must obviously + use 1 as a starting value instead of 0. +

The other three functions have similar dual-signature forms. +