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< a name = "fusion.algorithms.iteration.functions.fold" > < / a > < a href = "fold.html" title = "fold" > fold< / a > < / h5 > < / div > < / div > < / div >
< a name = "fusion.algorithms.iteration.functions.fold.description" > < / a > < h6 >
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< a name = "id550254" > < / a >
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< a href = "fold.html#fusion.algorithms.iteration.functions.fold.description" > Description< / a >
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< p >
Repeatedly applies binary < a href = "../../concepts/polymorphic_function_object.html" title = "Polymorphic
Function Object">Polymorphic
Function Object< / a > <EFBFBD> < tt class = "computeroutput" > < span class = "identifier" > f< / span > < / tt >
to each element of a sequence and the previous state.
< / p >
< a name = "fusion.algorithms.iteration.functions.fold.synopsis" > < / a > < h6 >
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< a name = "id550303" > < / a >
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< a href = "fold.html#fusion.algorithms.iteration.functions.fold.synopsis" > Synopsis< / a >
< / h6 >
< pre class = "programlisting" >
< span class = "keyword" > template< / span > < span class = "special" > < < / span >
< span class = "keyword" > typename< / span > < span class = "identifier" > Sequence< / span > < span class = "special" > ,< / span >
< span class = "keyword" > typename< / span > < span class = "identifier" > State< / span > < span class = "special" > ,< / span >
< span class = "keyword" > typename< / span > < span class = "identifier" > F< / span >
< span class = "special" > > < / span >
< span class = "keyword" > typename< / span > < a href = "../metafunctions/fold.html" title = "fold" > < tt class = "computeroutput" > < span class = "identifier" > result_of< / span > < span class = "special" > ::< / span > < span class = "identifier" > fold< / span > < / tt > < / a > < span class = "special" > < < / span > < span class = "identifier" > Sequence< / span > < span class = "special" > ,< / span > < span class = "identifier" > State< / span > < span class = "special" > ,< / span > < span class = "identifier" > F< / span > < span class = "special" > > ::< / span > < span class = "identifier" > type< / span > < span class = "identifier" > fold< / span > < span class = "special" > (< / span >
< span class = "identifier" > Sequence< / span > < span class = "special" > & < / span > < span class = "identifier" > seq< / span > < span class = "special" > ,< / span > < span class = "identifier" > State< / span > < span class = "keyword" > const< / span > < span class = "special" > & < / span > < span class = "identifier" > initial_state< / span > < span class = "special" > ,< / span > < span class = "identifier" > F< / span > < span class = "keyword" > const< / span > < span class = "special" > & < / span > < span class = "identifier" > f< / span > < span class = "special" > );< / span >
< / pre >
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< div class = "table" >
< a name = "id550562" > < / a > < p class = "title" > < b > Table<EFBFBD> 1.32.<2E> Parameters< / b > < / p >
< table class = "table" summary = "Parameters" >
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< colgroup >
< col >
< col >
< col >
< / colgroup >
< thead > < tr >
< th > Parameter< / th >
< th > Requirement< / th >
< th > Description< / th >
< / tr > < / thead >
< tbody >
< tr >
< td > < tt class = "computeroutput" > < span class = "identifier" > seq< / span > < / tt > < / td >
< td > A
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model of < a href = "../../../sequences/concepts/forward_sequence.html" title = "Forward
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Sequence">Forward
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Sequence< / a > ,< tt class = "computeroutput" > < span class = "identifier" > f< / span > < span class = "special" > (< / span > < span class = "identifier" > e< / span > < span class = "special" > )< / span > < / tt > must be a valid expression for each
element < tt class = "computeroutput" > < span class = "identifier" > e< / span > < / tt > in < tt class = "computeroutput" > < span class = "identifier" > seq< / span > < / tt >
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< / td >
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< td > Operation's argument< / td >
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< / tr >
< tr >
< td > < tt class = "computeroutput" > < span class = "identifier" > initial_state< / span > < / tt > < / td >
< td > Any
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type< / td >
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< td > Initial state< / td >
< / tr >
< tr >
< td > < tt class = "computeroutput" > < span class = "identifier" > f< / span > < / tt > < / td >
< td > A
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model of binary < a href = "../../concepts/polymorphic_function_object.html" title = "Polymorphic
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Function Object">Polymorphic
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Function Object< / a >
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< / td >
< td > Operation's argument< / td >
< / tr >
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< a name = "fusion.algorithms.iteration.functions.fold.expression_semantics" > < / a > < h6 >
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< a name = "id550730" > < / a >
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< a href = "fold.html#fusion.algorithms.iteration.functions.fold.expression_semantics" > Expression
Semantics< / a >
< / h6 >
< pre class = "programlisting" >
< span class = "identifier" > fold< / span > < span class = "special" > (< / span > < span class = "identifier" > seq< / span > < span class = "special" > ,< / span > < span class = "identifier" > initial_state< / span > < span class = "special" > ,< / span > < span class = "identifier" > f< / span > < span class = "special" > );< / span >
< / pre >
< p >
< span class = "bold" > < b > Return type< / b > < / span > : Any type
< / p >
< p >
< span class = "bold" > < b > Semantics< / b > < / span > : Equivalent to < tt class = "computeroutput" > < span class = "identifier" > f< / span > < span class = "special" > (< / span > < span class = "identifier" > eN< / span > <EFBFBD> < span class = "special" > ....< / span > < span class = "identifier" > f< / span > < span class = "special" > (< / span > < span class = "identifier" > e2< / span > < span class = "special" > ,< / span > < span class = "identifier" > f< / span > < span class = "special" > (< / span > < span class = "identifier" > e1< / span > < span class = "special" > ,< / span > < span class = "identifier" > initial_state< / span > < span class = "special" > )))< / span > < / tt >
where < tt class = "computeroutput" > < span class = "identifier" > e1< / span > <EFBFBD> < span class = "special" > ...< / span > < span class = "identifier" > eN< / span > < / tt > are the elements of < tt class = "computeroutput" > < span class = "identifier" > seq< / span > < / tt > .
< / p >
< a name = "fusion.algorithms.iteration.functions.fold.complexity" > < / a > < h6 >
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< a name = "id550935" > < / a >
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< a href = "fold.html#fusion.algorithms.iteration.functions.fold.complexity" > Complexity< / a >
< / h6 >
< p >
Linear, exactly < tt class = "computeroutput" > < a href = "../../../sequences/intrinsics/metafunctions/size.html" title = "size" > < tt class = "computeroutput" > < span class = "identifier" > result_of< / span > < span class = "special" > ::< / span > < span class = "identifier" > size< / span > < / tt > < / a > < span class = "special" > < < / span > < span class = "identifier" > Sequence< / span > < span class = "special" > > ::< / span > < span class = "identifier" > value< / span > < / tt > applications of < tt class = "computeroutput" > < span class = "identifier" > f< / span > < / tt > .
< / p >
< a name = "fusion.algorithms.iteration.functions.fold.header" > < / a > < h6 >
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< a name = "id551027" > < / a >
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< a href = "fold.html#fusion.algorithms.iteration.functions.fold.header" > Header< / a >
< / h6 >
< pre class = "programlisting" >
< span class = "preprocessor" > #include< / span > < span class = "special" > < < / span > < span class = "identifier" > boost< / span > < span class = "special" > /< / span > < span class = "identifier" > fusion< / span > < span class = "special" > /< / span > < span class = "identifier" > algorithm< / span > < span class = "special" > /< / span > < span class = "identifier" > iteration< / span > < span class = "special" > /< / span > < span class = "identifier" > fold< / span > < span class = "special" > .< / span > < span class = "identifier" > hpp< / span > < span class = "special" > > < / span >
< / pre >
< a name = "fusion.algorithms.iteration.functions.fold.example" > < / a > < h6 >
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< a name = "id551132" > < / a >
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< a href = "fold.html#fusion.algorithms.iteration.functions.fold.example" > Example< / a >
< / h6 >
< pre class = "programlisting" >
< span class = "keyword" > struct< / span > < span class = "identifier" > make_string< / span >
< span class = "special" > {< / span >
< span class = "keyword" > template< / span > < span class = "special" > < < / span > < span class = "keyword" > typename< / span > < span class = "identifier" > T< / span > < span class = "special" > ,< / span > < span class = "keyword" > typename< / span > < span class = "identifier" > State< / span > < span class = "special" > > < / span >
< span class = "keyword" > struct< / span > < span class = "identifier" > apply< / span >
< span class = "special" > {< / span >
< span class = "keyword" > typedef< / span > < span class = "identifier" > std< / span > < span class = "special" > ::< / span > < span class = "identifier" > string< / span > < span class = "identifier" > type< / span > < span class = "special" > ;< / span >
< span class = "special" > };< / span >
< span class = "keyword" > template< / span > < span class = "special" > < < / span > < span class = "keyword" > typename< / span > < span class = "identifier" > T< / span > < span class = "special" > > < / span >
< span class = "identifier" > std< / span > < span class = "special" > ::< / span > < span class = "identifier" > string< / span > < span class = "keyword" > operator< / span > < span class = "special" > ()(< / span > < span class = "keyword" > const< / span > < span class = "identifier" > T< / span > < span class = "special" > & < / span > < span class = "identifier" > t< / span > < span class = "special" > ,< / span > < span class = "keyword" > const< / span > < span class = "identifier" > std< / span > < span class = "special" > ::< / span > < span class = "identifier" > string< / span > < span class = "special" > & < / span > < span class = "identifier" > str< / span > < span class = "special" > )< / span > < span class = "keyword" > const< / span >
< span class = "special" > {< / span >
< span class = "keyword" > return< / span > < span class = "identifier" > str< / span > < span class = "special" > +< / span > < span class = "identifier" > boost< / span > < span class = "special" > ::< / span > < span class = "identifier" > lexical_cast< / span > < span class = "special" > < < / span > < span class = "identifier" > std< / span > < span class = "special" > ::< / span > < span class = "identifier" > string< / span > < span class = "special" > > (< / span > < span class = "identifier" > t< / span > < span class = "special" > );< / span >
< span class = "special" > }< / span >
< span class = "special" > };< / span >
< span class = "special" > ...< / span >
< span class = "keyword" > const< / span > < a href = "../../../sequences/containers/vector.html" title = "vector" > < tt class = "computeroutput" > < span class = "identifier" > vector< / span > < / tt > < / a > < span class = "special" > < < / span > < span class = "keyword" > int< / span > < span class = "special" > ,< / span > < span class = "keyword" > int< / span > < span class = "special" > > < / span > < span class = "identifier" > vec< / span > < span class = "special" > (< / span > < span class = "number" > 1< / span > < span class = "special" > ,< / span > < span class = "number" > 2< / span > < span class = "special" > );< / span >
< span class = "identifier" > assert< / span > < span class = "special" > (< / span > < a href = "fold.html" title = "fold" > < tt class = "computeroutput" > < span class = "identifier" > fold< / span > < / tt > < / a > < span class = "special" > (< / span > < span class = "identifier" > vec< / span > < span class = "special" > ,< / span > < span class = "identifier" > std< / span > < span class = "special" > ::< / span > < span class = "identifier" > string< / span > < span class = "special" > (< / span > < span class = "string" > ""< / span > < span class = "special" > ),< / span > < span class = "identifier" > make_string< / span > < span class = "special" > ())< / span > < span class = "special" > ==< / span > < span class = "string" > "12"< / span > < span class = "special" > );< / span >
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< td align = "right" > < small > Copyright <20> 2001-2005 Joel de Guzman, Dan Marsden< / small > < / td >
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