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| <H2>22.7 Non-Member Functions</H2> |
| <A NAME="2271"><H3>22.7.1 Binary Operators</H3></A> |
| <A NAME="idx472"><!></A> |
| <P>Class <B><I><A HREF="../stdlibref/valarray.html">valarray</A></I></B> provides a large block of binary operators that allow a program to apply these operators to two <B><I>valarray</I></B>s or to a <B><I>valarray</I></B> and a <SAMP>T</SAMP> value, where the <SAMP>T</SAMP> can occur on the left- or right-hand side of the expression. As you'd expect, these operators do not modify either of their arguments, but instead return a new <B><I>valarray</I></B> containing the result of the operation. Each version that takes two <B><I>valarray</I></B> arguments returns the result of applying the operation to the corresponding elements of the arrays. The versions with a <SAMP>T&</SAMP> argument return a <B><I>valarray</I></B> whose elements result from applying the operation to each element in the <B><I>valarray</I></B> argument along with the <SAMP>T&</SAMP> argument. See the <B><I>valarray</I></B> entry in the <A HREF="../stdlibref/noframes.html"><I>C++ Standard Library Module Reference Guide</I></A> for a complete list of binary operators.</P> |
| <P>Arithmetic and bitwise operators return a <B><I><A HREF="../stdlibref/valarray.html">valarray</A></I></B> of <SAMP>T</SAMP>. Logical operators return a <B><I>valarray<bool></I></B>, where each element represents the comparison of corresponding elements in two <B><I>valarray</I></B>s or the comparison of each element in an array with a particular value. For example:</P> |
| |
| <UL><PRE> |
| int a[3] = {1,2,3}; |
| int b[3] = {0,1,4}; |
| std::valarray<int> v1(a,3); |
| std::valarray<int> v2(b,3); |
| std::valarray<int> v3(0,3); |
| std::valarray<bool> v4(false,3); |
| v3 = v1 + v2; // v3 = {1,3,7} |
| v4 = v1 == v2; // v4 = {false,false,false} |
| v4 = v1 < v2; // v4 = {false,false,true} |
| </PRE></UL> |
| <A NAME="2272"><H3>22.7.2 Transcendental Functions</H3></A> |
| <A NAME="idx473"><!></A> |
| <P>Class <B><I><A HREF="../stdlibref/valarray.html">valarray</A></I></B> also provides 20 transcendental functions, four of which are overloads. Each function returns a new <B><I>valarray</I></B> that contains elements resulting from the application of the transcendental function to each element in the <B><I>valarray</I></B> passed as an argument. See the <B><I>valarray</I></B> entry in the <A HREF="../stdlibref/noframes.html"><I>C++ Standard Library Module Reference Guide</I></A> for a complete list of transcendental functions. </P> |
| <P>The following example squares each of the elements of an array:</P> |
| |
| <UL><PRE> |
| using std::pow; |
| |
| float a[3] = {2.0, 4.0, 16.0}; |
| std::valarray<float> v(a,3); // v = {2.0, 4.0, 16.0} |
| std::valarray<float> v2(0.0,3); // v2 = {0.0, 0.0, 0.0} |
| v2 = std::pow(v,2.0); // v2 = {4.0, 16.0, 256.0 } |
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