什么是元组?
元组是可以容纳许多元素的对象。元素可以是不同的数据类型。元组的元素被初始化为参数，以便可以访问它们。
元组上的操作：
1. get() ：-get()用于访问元组值并对其进行修改，它接受索引和元组名称作为访问特定元组元素的参数。
2. make_tuple() ：-make_tuple()用于为元组分配值。传递的值应与在元组中声明的值一致。
// C++ code to demonstrate tuple, get() and make_pair()
#include
#include // for tuple
using namespace std;
int main()
{
// Declaring tuple
tuple geek;
// 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<0>(geek) << " " << get<1>(geek);
cout << " " << get<2>(geek) << endl;
// Use of get() to change values of tuple
get<0>(geek) = 'b';
get<2>(geek) = 20.5;
// Printing modified tuple values
cout << "The modified values of tuple are : ";
cout << get<0>(geek) << " " << get<1>(geek);
cout << " " << get<2>(geek) << endl;
return 0;
}
输出：
The initial values of tuple are : a 10 15.5
The modified values of tuple are : b 10 20.5
在上面的代码中，get()修改元组的第一和第三值。
3. tuple_size ：-返回元组中存在的元素数。
//C++ code to demonstrate tuple_size
#include
#include // for tuple_size and tuple
using namespace std;
int main()
{
// Initializing tuple
tuple geek(20,'g',17.5);
// Use of size to find tuple_size of tuple
cout << "The size of tuple is : ";
cout << tuple_size::value << endl;
return 0;
}
输出：
The size of tuple is : 3
4. swap() ：-swap()交换两个不同元组的元素。
//C++ code to demonstrate swap()
#include
#include // for swap() and tuple
using namespace std;
int main()
{
// Initializing 1st tuple
tuple tup1(20,'g',17.5);
// Initializing 2nd tuple
tuple tup2(10,'f',15.5);
// Printing 1st and 2nd tuple before swapping
cout << "The first tuple elements before swapping are : ";
cout << get<0>(tup1) << " " << get<1>(tup1) << " "
<< get<2>(tup1) << endl;
cout << "The second tuple elements before swapping are : ";
cout << get<0>(tup2) << " " << get<1>(tup2) << " "
<< get<2>(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<0>(tup1) << " " << get<1>(tup1) << " "
<< get<2>(tup1) << endl;
cout << "The second tuple elements after swapping are : ";
cout << get<0>(tup2) << " " << get<1>(tup2) << " "
<< get<2>(tup2) << endl;
return 0;
}
输出：
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. tie() ： tie()的工作是将元组值解包到单独的变量中。 tie()有两种变体，有和没有“ ignore”，“ ignore”将忽略特定的元组元素并阻止其解压缩。
// 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 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;
}
输出：
The unpacked tuple values (without ignore) are : 20 g 17.5
The unpacked tuple values (with ignore) are : 20 17.5
6. tuple_cat() ：-此函数连接两个元组并返回一个新的元组。
// C++ code to demonstrate working of tuple_cat()
#include
#include // for tuple_cat() and tuple
using namespace std;
int main()
{
// Initializing 1st tuple
tuple tup1(20,'g',17.5);
// Initializing 2nd tuple
tuple tup2(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<0>(tup3) << " " << get<1>(tup3) << " ";
cout << get<2>(tup3) << " " << get<3>(tup3) << " ";
cout << get<4>(tup3) << " " << get<5>(tup3) << endl;
return 0;
}
输出：
The new tuple elements in order are : 20 g 17.5 30 f 10.5
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