Java中的 Stack contains() 方法和示例
Java.util.Stack.contains()方法用于检查特定元素是否存在于堆栈中。所以基本上它用于检查堆栈是否包含任何特定元素。
句法:
Stack.contains(Object element)
参数:此方法采用堆栈类型的强制参数元素。这是需要测试的元素是否存在于堆栈中。
返回值:如果元素存在于堆栈中,则此方法返回True ,否则返回False 。
下面的程序说明了Java.util.Stack.contains() 方法:
方案一:
// Java code to illustrate contains()
import java.util.*;
public class StackDemo {
public static void main(String args[])
{
// Creating an empty Stack
Stack stack = new Stack();
// Use add() method to add elements into the Stack
stack.add("Welcome");
stack.add("To");
stack.add("Geeks");
stack.add("4");
stack.add("Geeks");
// Displaying the Stack
System.out.println("Stack: " + stack);
// Check for "Geeks" in the Stack
System.out.println("Does the Stack contains 'Geeks'? "
+ stack.contains("Geeks"));
// Check for "4" in the Stack
System.out.println("Does the Stack contains '4'? "
+ stack.contains("4"));
// Check if the Queue contains "No"
System.out.println("Does the Stack contains 'No'? "
+ stack.contains("No"));
}
}
输出:
Stack: [Welcome, To, Geeks, 4, Geeks]
Does the Stack contains 'Geeks'? true
Does the Stack contains '4'? true
Does the Stack contains 'No'? false
方案二:
// Java code to illustrate contains()
import java.util.*;
public class StackDemo {
public static void main(String args[])
{
// Creating an empty Stack
Stack stack = new Stack();
// Use add() method to add elements into the Stack
stack.add(10);
stack.add(15);
stack.add(30);
stack.add(20);
stack.add(5);
// Displaying the Stack
System.out.println("Stack: " + stack);
// Check for "Geeks" in the Stack
System.out.println("Does the Stack contains 'Geeks'? "
+ stack.contains("Geeks"));
// Check for "4" in the Stack
System.out.println("Does the Stack contains '4'? "
+ stack.contains("4"));
// Check if the Stack contains "No"
System.out.println("Does the Stack contains 'No'? "
+ stack.contains("No"));
}
}
输出:
Stack: [10, 15, 30, 20, 5]
Does the Stack contains 'Geeks'? false
Does the Stack contains '4'? false
Does the Stack contains 'No'? false