Tuples i C++
Hvad er en tupel?
En tupel er en genstand, der kan rumme en række elementer. Elementerne kan være af forskellige datatyper. Elementerne i tupler initialiseres som argumenter i den rækkefølge, de vil blive tilgået.
Operationer på tuple :-
1. få() :- get() bruges til at få adgang til tupelværdierne og ændre dem, det accepterer indekset og tupelnavnet som argumenter for at få adgang til et bestemt tupelelement.
2. make_tuple() :- make_tuple() bruges til at tildele tuple med værdier. De beståede værdier skal være i orden med værdierne angivet i tuple.
CPP
// C++ code to demonstrate tuple, get() and make_pair()> #include> #include // for tuple> using> namespace> std;> int> main()> {> > // Declaring tuple> > tuple <> char> ,> int> ,> float> >nørd;> > // Assigning values to tuple using make_tuple()> > geek = make_tuple(> 'a'> , 10, 15.5);> > // Printing initial tuple values using get()> > cout < < 'The initial values of tuple are : ';> > cout < < get(geek) < < ' ' < < get(geek);> > cout < < ' ' < < get(geek) < < endl;> > // Use of get() to change values of tuple> > get(geek) => 'b'> ;> > get(geek) = 20.5;> > // Printing modified tuple values> > cout < < 'The modified values of tuple are : ';> > cout < < get(geek) < < ' ' < < get(geek);> > cout < < ' ' < < get(geek) < < endl;> > return> 0;> }> |
Produktion:
The initial values of tuple are : a 10 15.5 The modified values of tuple are : b 10 20.5
I ovenstående kode ændrer get() 1. og 3. værdi af tuple.
3. tuple_size :- Det returnerer antallet af elementer, der er til stede i tuplet.
CPP
//C++ code to demonstrate tuple_size> #include> #include // for tuple_size and tuple> using> namespace> std;> int> main()> {> > // Initializing tuple> > tuple <> char> ,> int> ,> float> >nørd(20,> 'g'> ,17.5);> > // Use of size to find tuple_size of tuple> > cout < < 'The size of tuple is : ';> > cout < < tuple_size <> decltype> (geek)>::værdi < < endl;> > return> 0;> }> |
Produktion:
The size of tuple is : 3
4. swap() :- Swap(), bytter elementerne i de to forskellige tupler.
CPP
//C++ code to demonstrate swap()> #include> #include // for swap() and tuple> using> namespace> std;> int> main()> {> > // Initializing 1st tuple> > tuple <> int> ,> char> ,> float> >tup1(20,> 'g'> ,17.5);> > > // Initializing 2nd tuple> > tuple <> int> ,> char> ,> float> >stump2(10,> 'f'> ,15.5);> > > // Printing 1st and 2nd tuple before swapping> > cout < < 'The first tuple elements before swapping are : ';> > cout < < get(tup1) < < ' ' < < get(tup1) < < ' '> > < < get(tup1) < < endl;> > cout < < 'The second tuple elements before swapping are : ';> > cout < < get(tup2) < < ' ' < < get(tup2) < < ' '> > < < get(tup2) < < endl;> > > // Swapping tup1 values with tup2> > tup1.swap(tup2);> > > // Printing 1st and 2nd tuple after swapping> > cout < < 'The first tuple elements after swapping are : ';> > cout < < get(tup1) < < ' ' < < get(tup1) < < ' '> > < < get(tup1) < < endl;> > cout < < 'The second tuple elements after swapping are : ';> > cout < < get(tup2) < < ' ' < < get(tup2) < < ' '> > < < get(tup2) < < endl;> > return> 0;> }> |
Produktion:
The first tuple elements before swapping are : 20 g 17.5 The second tuple elements before swapping are : 10 f 15.5 The first tuple elements after swapping are : 10 f 15.5 The second tuple elements after swapping are : 20 g 17.5
5. uafgjort() :- Arbejdet med tie() er at udpakke tupelværdierne i separate variable. Der er to varianter af tie(), med og uden ignore , ignorer ignorerer et bestemt tuple-element og forhindrer det i at blive pakket ud.
CPP
// C++ code to demonstrate working of tie()> #include> #include // for tie() and tuple> using> namespace> std;> int> main()> {> > // Initializing variables for unpacking> > int> i_val;> > char> ch_val;> > float> f_val;> > > // Initializing tuple> > tuple <> int> ,> char> ,> float> >tup1(20,> 'g'> ,17.5);> > // Use of tie() without ignore> > tie(i_val,ch_val,f_val) = tup1;> > > // Displaying unpacked tuple elements> > // without ignore> > cout < < 'The unpacked tuple values (without ignore) are : ';> > cout < < i_val < < ' ' < < ch_val < < ' ' < < f_val;> > cout < < endl;> > > // Use of tie() with ignore> > // ignores char value> > tie(i_val,ignore,f_val) = tup1;> > > // Displaying unpacked tuple elements> > // with ignore> > cout < < 'The unpacked tuple values (with ignore) are : ';> > cout < < i_val < < ' ' < < f_val;> > cout < < endl;> > return> 0;> }> |
Produktion:
The unpacked tuple values (without ignore) are : 20 g 17.5 The unpacked tuple values (with ignore) are : 20 17.5
6. tuple_cat() :- Denne funktion sammenkæder to tupler og returnerer en ny tuple.
CPP
// C++ code to demonstrate working of tuple_cat()> #include> #include // for tuple_cat() and tuple> using> namespace> std;> int> main()> {> > // Initializing 1st tuple> > tuple <> int> ,> char> ,> float> >tup1(20,> 'g'> ,17.5);> > // Initializing 2nd tuple> > tuple <> int> ,> char> ,> float> >stump2(30,> 'f'> ,10.5);> > > // Concatenating 2 tuples to return a new tuple> > auto> tup3 = tuple_cat(tup1,tup2);> > > // Displaying new tuple elements> > cout < < 'The> new> tuple elements in order are : ';> > cout < < get(tup3) < < ' ' < < get(tup3) < < ' ';> > cout < < get(tup3) < < ' ' < < get(tup3) < < ' ';> > cout < < get(tup3) < < ' ' < < get(tup3) < < endl;> > return> 0;> }> |
Produktion:
The new tuple elements in order are : 20 g 17.5 30 f 10.5
