[ bane @ 30.03.2002. 14:42 ] @
| Koristim Borland C++ kompajler 5.02. Radeći primere iz knjige Stanley B. Lippmana Osnove jezika C++ naiso sam na problem koji prati sve primere u kojim se korista šabloni. Evo jedan primer iz knjige. /************************************************** * Essential C++ -- Stanley Lippman * Addison-Wesley * ISBN 0-201-48518-4 * homepage: www.objectwrite.com * email: [email protected] *************************************************/ #include <iostream> #include <fstream> #include <functional> #include <algorithm> #include <vector> #include <string> using namespace std; // globals as convenience for executing procedures const int int_size = 12; const int string_size = 4; const int int_not_present = 1024; int ia[int_size] = { 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144 }; string sa[string_size] = { "pooh", "piglet", "eeyore", "tigger" }; vector<int> ivec( ia, ia+int_size ); vector<string> svec( sa, sa+string_size ); // iterative versions of find() in Section 3.1 const int* find_ver1( const vector<int> &vec, int value ) { for ( int ix = 0; ix < vec.size(); ++ix ) if ( vec[ ix ] == value ) return &vec[ ix ]; return 0; } template <typename elemType> const elemType* find_ver2( const vector<elemType> &vec, const elemType &value ) { for ( int ix = 0; ix < vec.size(); ++ix ) if ( vec[ ix ] == value ) return &vec[ ix ]; return 0; } template <typename elemType> inline const elemType* begin( const vector<elemType> &vec ) { return vec.empty() ? 0 : &vec[0]; } template <typename elemType> inline const elemType* end( const vector<elemType> &vec ) { return vec.empty() ? 0 : &vec[vec.size()]; } template <typename elemType> const elemType* find_ver3( const elemType *array, int size, const elemType &value ) { if ( ! array || size < 1 ) return 0; for ( int ix = 0; ix < size; ++ix ) // we can apply subscript operator to pointer if ( array[ ix ] == value ) return &array[ ix ]; return 0; // value not found } template <typename elemType> const elemType* find_ver4( const elemType *array, int size, const elemType &value ) { if ( ! array || size < 1 ) return 0; // ++array increments array by one elememt for ( int ix = 0; ix < size; ++ix, ++array ) // *array dereferences the address if ( *array == value ) return array; return 0; } template <typename elemType> const elemType* find_ver5( const elemType *first, const elemType *last, const elemType &value ) { if ( ! first || ! last ) return 0; // while first does not equal last, // compare value with element addressed by first // if the two are equal, return first // otherwise, increment first to address next element for ( ; first != last; ++first ) if ( *first == value ) return first; return 0; } // Section 3.2 version of find template <typename IteratorType, typename elemType > IteratorType find_ver6( IteratorType first, IteratorType last, const elemType &value ) { for ( ; first != last; ++first ) if ( value == *first ) return first; return last; } void prog_find_vers() { const int *iptr = find_ver1( ivec, ivec[2] ); if ( iptr != &ivec[2] ) cerr << "?? find_ver1 failed!n"; else cerr << "!! find_ver1 ok!n"; const string* sptr = find_ver2( svec, svec[2] ); if ( sptr != &svec[2] ) cerr << "?? find_ver2 failed with string!n"; else cerr << "!! find_ver2 ok with string!n"; iptr = find_ver2( ivec, ivec[2] ); if ( iptr != &ivec[2] ) cerr << "?? find_ver2 failed with int!n"; else cerr << "!! find_ver2 ok with int!n"; iptr = find_ver3( ia, int_size, ia[2] ); if ( iptr != &ia[2] ) cerr << "?? find_ver3 failed with int array!n"; else cerr << "!! find_ver3 ok with int array!n"; sptr = find_ver3( sa, string_size, sa[2] ); if ( sptr != &sa[2] ) cerr << "?? find_ver3 failed with string array!n"; else cerr << "!! find_ver3 ok with string array!n"; iptr = find_ver4( begin( ivec ), ivec.size(), ivec[2] ); if ( iptr != &ivec[2] ) cerr << "?? find_ver4 failed with int vector!n"; else cerr << "!! find_ver4 ok with int vector!n"; sptr = find_ver4( begin( svec ), svec.size(), svec[2] ); if ( sptr != &svec[2] ) cerr << "?? find_ver4 failed with string vector!n"; else cerr << "!! find_ver4 ok with string vector!n"; sptr = find_ver5( sa, sa+string_size, sa[2] ); if ( sptr != &sa[2] ) cerr << "?? find_ver5 failed with string array!n"; else cerr << "!! find_ver5 ok with string array!n"; iptr = find_ver5( begin( ivec ), end( ivec ), ivec[2] ); if ( iptr != &ivec[2] ) cerr << "?? find_ver5 failed with int vector!n"; else cerr << "!! find_ver5 ok with int vector!n"; iptr = find_ver5( begin( ivec ), end( ivec ), int_not_present ); if ( iptr != 0 ) cerr << "?? find_ver5 failed with int not present in vector!n"; else cerr << "!! find_ver5 ok with int not present in vector!n"; sptr = find_ver6( sa, sa+string_size, sa[2] ); if ( sptr != &sa[2] ) cerr << "?? find_ver6 failed with string array and iterators!n"; else cerr << "!! find_ver3 ok with string array and iterators!n"; vector< int >::iterator it; it = find_ver6( ivec.begin(), ivec.end(), ivec[2] ); if ( *it != ivec[2] ) cerr << "?? find_ver6 failed with int vector and iterators!n"; else cerr << "!! find_ver4 ok with int vector and iterators!n"; } // from Section 3.6: How to Design a Generic Algorithm vector<int> less_than_10( const vector<int> &vec ) { vector<int> nvec; for ( int ix = 0; ix < vec.size(); ++ix ) if ( vec[ ix ] < 10 ) nvec.push_back( vec[ ix ] ); return nvec; } bool less_than( int v1, int v2 ) { return v1 < v2 ? true : false; } bool greater_than( int v1, int v2 ) { return v1 > v2 ? true : false; } vector<int> filter_ver1( const vector<int> &vec, int filter_value, bool (*pred)( int, int )) { vector<int> nvec; for ( int ix = 0; ix < vec.size(); ++ix ) // invokes the function addressed by pred // tests element vec[ix] against filter_value if ( pred( vec[ ix ], filter_value )) nvec.push_back( vec[ ix ] ); return nvec; } vector<int> filter_ver2( const vector<int> &vec, int val, less<int> < ) { vector<int> nvec; vector<int>::const_iterator iter = vec.begin(); // bind2nd( less<int>, val ) // binds val to the second value of less<int> // less<int> now compares each value against val while (( iter = find_if( iter, vec.end(), bind2nd( lt, val ))) != vec.end() ) { // each time iter != vec.end(), // iter addresses an element less than val nvec.push_back( *iter ); iter++; } return nvec; } template <typename InputIterator, typename OutputIterator, typename ElemType, typename Comp> OutputIterator filter_ver3( InputIterator first, InputIterator last, OutputIterator at, const ElemType &val, Comp pred ) { while (( first = find_if( first, last, bind2nd( pred, val ))) != last ) // assign value, then advance both iterators *at++ = *first++; return at; } vector<int> sub_vec( const vector<int> &vec, int val ) { vector<int> local_vec( vec ); sort( local_vec.begin(), local_vec.end() ); vector<int>::iterator iter = find_if( local_vec.begin(), local_vec.end(), bind2nd( greater<int>(), val )); local_vec.erase( iter, local_vec.end() ); return local_vec; } void prog_filter_vers() { const int solution_size = 6; vector<int> local_vec = less_than_10( ivec ); if ( local_vec.size() != solution_size ) cerr << "?? less_than_10 failed! expected expected " << solution_size << ", received: " << local_vec.size() << endl; else cerr << "!! less_than_10 ok!n"; const int partition_value = 10; local_vec = filter_ver1( ivec, partition_value, greater_than ); if ( local_vec.size() != solution_size ) cerr << "?? filter_ver1 failed! expected expected " << solution_size << ", received: " << local_vec.size() << endl; else cerr << "!! filter_ver1 ok!n"; local_vec = filter_ver2( ivec, partition_value, less<int>() ); if ( local_vec.size() != solution_size ) cerr << "?? filter_ver2 failed! expected " << solution_size << ", received: " << local_vec.size() << endl; else cerr << "!! filter_ver2 ok!n"; // unless we use an iserter, must provide a sized container // within which filter can assign the values ... int ia2[ solution_size ]; filter_ver3( ia, ia+int_size, ia2, partition_value, less<int>() ); int err_cnt = 0; for ( int ix = 0; ix < solution_size; ++ix ) if ( ia[ ix ] != ia2[ ix ] ) ++err_cnt; if ( err_cnt ) cerr << "?? filter_ver3 failed for array! " << err_cnt << " unexpected valuesn"; else cerr << "!! filter_ver3 for array ok!n"; vector<int> ivec2( solution_size ); filter_ver3( ivec.begin(), ivec.end(), ivec2.begin(), partition_value, greater<int>() ); err_cnt = 0; ix = solution_size; for ( int iy = 0; ix < ivec.size(); ++ix, ++iy ) if ( ivec[ ix ] != ivec2[ iy ] ) ++err_cnt; if ( err_cnt ) cerr << "?? filter_ver3 failed for vector! " << err_cnt << " unexpected valuesn"; else cerr << "!! filter_ver3 for vector ok!n"; // illustrate using an inserter vector<int> ivec3; filter_ver3( ivec.begin(), ivec.end(), back_inserter( ivec3 ), partition_value, greater<int>() ); if ( ivec3.size() != solution_size ) cerr << "?? filter_ver3 with back inserter failed! expected " << solution_size << ", received: " << ivec3.size() << endl; else cerr << "!! filter_ver3 with back inserter ok!n"; ivec3 = sub_vec( ivec, partition_value ); if ( ivec3.size() != solution_size ) cerr << "?? sub_vec failed! expected " << solution_size << ", received: " << ivec3.size() << endl; else cerr << "!! sub_vec ok!n"; } // Section 3.10 iostream_iterator examples void prog_io_std() { cout << "please enter some text, then indicate end of file!n"; istream_iterator< string > is( cin ); istream_iterator< string > eof; vector< string > text; copy( is, eof, back_inserter( text )); sort( text.begin(), text.end() ); ostream_iterator<string> os( cout, " " ); copy( text.begin(), text.end(), os ); } void prog_io_fil() { ifstream in_file( "input_file.txt" ); ofstream out_file( "output_file.txt" ); if ( ! in_file || ! out_file ) { cerr << "?? unable to open the necessary files.n"; return; } else cerr << "!! ok: input and output files opened!n"; istream_iterator< string > is( in_file ); istream_iterator< string > eof; vector< string > text; copy( is, eof, back_inserter( text )); if ( text.empty() ) cerr << "?? iostream iterators failed: string vector empty!n"; else cerr << "!! iostream iterators seem to work: " << text.size() << " strings read in!n"; sort( text.begin(), text.end() ); ostream_iterator<string> os( out_file, " " ); unique_copy( text.begin(), text.end(), os ); } void prog_io_iters() { // prog_io_std(); prog_io_fil(); } int main() { cerr << "About to execute prog_find_vers()nn"; prog_find_vers(); cerr << "nnAbout to execute prog_filter_vers()nn"; prog_filter_vers(); cerr << "nnAbout to execute prog_io_iters()nn"; prog_io_iters(); cerr << "nnOk -- done!nn"; return 0; // quiet vc6++ } **************************************************************************************************************************************************************************** Info :ch3_main.cpp: out of date with destination ch3_main.obj Info : ch3_main.cpp: source date 1:16:24 PM 12/7/1999 destination date <unknown> Info :Compiling C:My Documentsstanely B primjerinon_windowscodeEssentialsourcechapter3chap3ch3_main.cpp Warn : string.h(549,3):Functions containing for are not expanded inline Warn : string.h(557,3):Functions containing while are not expanded inline Warn : string.h(563,3):Functions containing for are not expanded inline Warn : string.h(575,3):Functions containing for are not expanded inline Warn : string.cc(686,32):Comparing signed and unsigned values Warn : VECTOR.h(985,2):Cannot create pre-compiled header: code in header Warn : ch3_main.cpp(31,27):Comparing signed and unsigned values Error: ch3_main.cpp(37,28):Type name expected Error: ch3_main.cpp(38,2):Templates must be classes or functions |