添加元素到堆栈

Question

我在这个方法中创建一个堆栈调用添加方法我想添加元素后，元素是特定的形式使用例如，如果堆栈中的数字是“1 2 3 5”，我选择数字3和进入4号堆应该是“​​1 2 3 4 5”这个我想

int a[] = new int[6]; 
int Top = -1; 

public void push() { 
    if (Top > 6) { 
     System.out.println(" the Stack Ovelflow"); 
    } else { 
     Top = Top + 1; 
     String m = JOptionPane.showInputDialog("enter the element stack"); 
     a[Top] = Integer.parseInt(m); 
    } 
} 

public void adding() { 
    String s = JOptionPane.showInputDialog("enter the element u want to add after it"); 
    int x = Integer.parseInt(s); 
    String s2 = JOptionPane.showInputDialog("enter the element u want to add to stack"); 
    int d = Integer.parseInt(s2); 
    for (int i = 0; i < a.length; i++) { 
     if (a[i] == x) { 
      a[i + 1] = d; 
     } 
    } 
} 

Answer 1

你需要确保你的支持数组a有足够的空间，让您可以插入一个新元素。

int[] a= new int[]{1,2,3,5}; // this has only 4 elements, you can't add a 5th 

所以，你可以这样做：

public void adding(){ 
    // ask user for input.... and all that 
    // you need an array with one more element than a. lets call it b 

    int[] b = new int[a.length + 1]; 

    // now you need to search for x. (this is, if x is a number in your array and not an index..it wasn't clear to me) 
    // so if x is a number in the array (and not the index) you need to get the index of that number: 
    int index = 0; 
    for (; index < a.length; index++) { // your index variable will increment on each step 
     if (a[index] == x) { 
      break;   // and you break out of the loop once you found x 
     } 
    } 

    // now you know the index of x 
    // first make a copy of the partial array after x (in your example its just {5}) 
    int[] c = Arrays.copyOfRange(a, index, a.length); // this will copy all elements of a from "index" to "length" 

    // and here the loop that will actually insert the new number and move the rest: 

    int cIndex=0; // we need that counter later to loop through the new array c 
    for (int i = 0; i < b.length; i++) { // loop through every element of b 
     if (i <= index) { // if i is currently smaller than your wanted index (there where you will find x) 
      b[i] = a[i]; // then just copy the contents of a 
     } else if (i == index+1) { // we just stepped over x 
      b[i] = d;   // so you can add your new number here 
     } else { 
      b[i] = c[cIndex]; // and here you copy the rest into b (the partial array we called c earlier) 
      cIndex++; // we need that new index, to get always the next element 
     }    
    } 

就是这样。看起来很复杂，而且迄今还不是最好或最有效的解决方案。但它的工作原理，我希望它可以帮助你更进一步！