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法律研究STL 集合中的插入和删除 C++
插入
通过 insert() 和 emplace() 操作可在 STL 集合中插入元素。
Insert()：Insert() 用于向集合插入元素。Insert 操作引用一个对象。
使用以下函数列表
- st.size() = 返回集合大小。
- st.insert() = 用于向集合插入元素。
示例代码
#include <iostream>
#include <set>
#include <string>
#include <cstdlib>
using namespace std;
int main() {
set<int> st;
set<int>::iterator it;
int c, i;
while (1) {
cout<<"1.Size of the Set"<<endl;
cout<<"2.Insert Element into the Set"<<endl;
cout<<"3.Display the set: "<<endl;
cout<<"4.Exit"<<endl;
cout<<"Enter your Choice: ";
cin>>c;
switch(c) {
case 1:
cout<<"Size of the Set: ";
cout<<st.size()<<endl;
break;
case 2:
cout<<"Enter value to be inserted: ";
cin>>i;
st.insert(i);
break;
case 3:
cout<<"Displaying Set by Iterator: ";
for (it = st.begin(); it != st.end(); it++) {
cout << (*it)<<" ";
}
cout<<endl;
break;
case 4:
exit(1);
break;
default:
cout<<"Wrong Choice"<<endl;
}
}
return 0;
}输出
1.Size of the Set 2.Insert Element into the Set 3.Display the set: 4.Exit Enter your Choice: 1 Size of the Set: 0 1.Size of the Set 2.Insert Element into the Set 3.Display the set: 4.Exit Enter your Choice: 2 Enter value to be inserted: 4 1.Size of the Set 2.Insert Element into the Set 3.Display the set: 4.Exit Enter your Choice: 2 Enter value to be inserted: 6 1.Size of the Set 2.Insert Element into the Set 3.Display the set: 4.Exit Enter your Choice: 2 Enter value to be inserted: 8 1.Size of the Set 2.Insert Element into the Set 3.Display the set: 4.Exit Enter your Choice: 2 Enter value to be inserted: 10 1.Size of the Set 2.Insert Element into the Set 3.Display the set: 4.Exit Enter your Choice: 3 Displaying Set by Iterator: 4 6 8 10 1.Size of the Set 2.Insert Element into the Set 3.Display the set: 4.Exit Enter your Choice: 4 Exit code: 1
Emplace()
Emplace 操作还用于就地向集合插入元素。它避免了不必要的对象复制，并比插入操作更有效率地执行插入。
使用的函数列表
- st.size() = 返回集合大小。
- st.emplace() = 用于向集合插入元素。
示例代码
#include <iostream>
#include <set>
#include <string>
#include <cstdlib>
using namespace std;
int main() {
set<int> st;
set<int>::iterator it;
int c, i;
while (1) {
cout<<"1.Size of the Set"<<endl;
cout<<"2.Insert Element into the Set"<<endl;
cout<<"3.Display the set: "<<endl;
cout<<"4.Exit"<<endl;
cout<<"Enter your Choice: ";
cin>>c;
switch(c) {
case 1:
cout<<"Size of the Set: ";
cout<<st.size()<<endl;
break;
case 2:
cout<<"Enter value to be inserted: ";
cin>>i;
st.emplace(i);
break;
case 3:
cout<<"Displaying Set by Iterator: ";
for (it = st.begin(); it != st.end(); it++) {
cout << (*it)<<" ";
}
cout<<endl;
break;
case 4:
exit(1);
break;
default:
cout<<"Wrong Choice"<<endl;
}
}
return 0;
}输出
1.Size of the Set 2.Insert Element into the Set 3.Display the set: 4.Exit Enter your Choice: 1 Size of the Set: 0 1.Size of the Set 2.Insert Element into the Set 3.Display the set: 4.Exit Enter your Choice: 2 Enter value to be inserted: 4 1.Size of the Set 2.Insert Element into the Set 3.Display the set: 4.Exit Enter your Choice: 6 Wrong Choice 1.Size of the Set 2.Insert Element into the Set 3.Display the set: 4.Exit Enter your Choice: 2 Enter value to be inserted: 6 1.Size of the Set 2.Insert Element into the Set 3.Display the set: 4.Exit Enter your Choice: 2 Enter value to be inserted: 7 1.Size of the Set 2.Insert Element into the Set 3.Display the set: 4.Exit Enter your Choice: 2 Enter value to be inserted: 8 1.Size of the Set 2.Insert Element into the Set 3.Display the set: 4.Exit Enter your Choice: 3 Displaying Set by Iterator: 4 6 7 8 1.Size of the Set 2.Insert Element into the Set 3.Display the set: 4.Exit Enter your Choice: 4 Exit code: 1
删除
使用 erase() 函数， 我们可以通过提及它的参数来从集合中删除元素，参数包括其位置、其值或一个数字范围。
此处使用的函数列表
- st.size() = 返回集合大小。
- st.insert() = 用于向集合插入元素。
- st.erase() = 从集合中删除元素
示例代码
#include <iostream>
#include <set>
#include <string>
#include <cstdlib>
using namespace std;
int main() {
set<int> st;
set<int>::iterator it;
int c, i;
while (1) {
cout<<"1.Size of the Set"<<endl;
cout<<"2.Insert Element into the Set"<<endl;
cout<<"3.Delete Element from the Set"<<endl;
cout<<"4.Display the set: "<<endl;
cout<<"5.Exit"<<endl;
cout<<"Enter your Choice: ";
cin>>c;
switch(c) {
case 1:
cout<<"Size of the Set: ";
cout<<st.size()<<endl;
break;
case 2:
cout<<"Enter value to be inserted: ";
cin>>i;
st.insert(i);
break;
case 3:
cout<<"Enter the element to be deleted: ";
cin>>i;
st.erase(i);
break;
case 4:
cout<<"Displaying Set by Iterator: ";
for (it = st.begin(); it != st.end(); it++) {
cout << (*it)<<" ";
}
cout<<endl;
break;
case 5:
exit(1);
break;
default:
cout<<"Wrong Choice"<<endl;
}
}
return 0;
}输出
1.Size of the Set 2.Insert Element into the Set 3.Delete Element from the Set 4.Display the set: 5.Exit Enter your Choice: 1 Size of the Set: 0 1.Size of the Set 2.Insert Element into the Set 3.Delete Element from the Set 4.Display the set: 5.Exit Enter your Choice: 2 Enter value to be inserted: 1 1.Size of the Set 2.Insert Element into the Set 3.Delete Element from the Set 4.Display the set: 5.Exit Enter your Choice: 2 Enter value to be inserted: 2 1.Size of the Set 2.Insert Element into the Set 3.Delete Element from the Set 4.Display the set: 5.Exit Enter your Choice: 2 Enter value to be inserted: 3 1.Size of the Set 2.Insert Element into the Set 3.Delete Element from the Set 4.Display the set: 5.Exit Enter your Choice: 2 Enter value to be inserted: 4 1.Size of the Set 2.Insert Element into the Set 3.Delete Element from the Set 4.Display the set: 5.Exit Enter your Choice: 4 Displaying Set by Iterator: 1 2 3 4 1.Size of the Set 2.Insert Element into the Set 3.Delete Element from the Set 4.Display the set: 5.Exit Enter your Choice: 3 Enter the element to be deleted: 2 1.Size of the Set 2.Insert Element into the Set 3.Delete Element from the Set 4.Display the set: 5.Exit Enter your Choice: 4 Displaying Set by Iterator: 1 3 4 1.Size of the Set 2.Insert Element into the Set 3.Delete Element from the Set 4.Display the set: 5.Exit Enter your Choice: 5 Exit code: 1
更新于： 2019 年 7 月 30 日
900 次观看
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