在c ++中向数组添加索引和指定的数字

Question

我正在创建一个程序，从用户从数组中提供的索引中删除一个数字，显示新数组，然后要求用户在他们选择的任何索引处插入一个数字。在删除索引时，此程序的第一部分工作正常，但我在添加索引和数字时遇到问题。例如，如果用户从索引5中删除数字后的NEW数组是：12 34 45 2 8 16 180 182 22，如果您记住数组从0开始是正确的，那么它们会请求添加示例索引5再次使用数字78，它变得搞砸了。它显示12 34 45 2 78 8 16 180 182 22（然后由于某种原因它还输出数字-858993460？）所以问题基本上是它应该在它之前添加新索引和第一个索引。我很抱歉，如果这听起来如此令人困惑，但我已经坚持了好几个小时。谢谢！

//This program demos basic arrays

#include <iostream>
using namespace std;

const int CAP = 10;

int main()
{
    int size;
    int list[CAP] = { 12, 34, 45, 2, 8, 10, 16, 180, 182, 22 };
    size = 10;
    int i, delIndex, addIndex, newInt = 0;

    cout << "Your list is: " << endl;
    for (i = 0; i < CAP; i++)
    {
        cout << list[i] << endl;
    } 

//Deleting an index

cout << "\nPlease enter index to delete from: ";
cin >> delIndex;

for (i = delIndex; i <= 10; i++)
{
    list[i] = list[i + 1];

}

cout << "The index position you specified has been deleted." << endl;
cout << "The new array is: " << endl;
for (i = 0; i < (size - 1); i++)
{
    cout << list[i] << endl;
}

//Adding an index

cout << "\nNow, please enter the index position to add to: " << endl;
cin >> addIndex;
cout << "\nEnter the number to add to the index: " << endl;
cin >> newInt;

for (i = size - 1; i >= addIndex - 1; i--)
{
    list[i + 1] = list[i];
}
        list[addIndex - 1] = newInt;
        size++;

    cout << "The number has been added at the specified index position." << 
endl;
    cout << "The new array is: " << endl;
    for (i = 0; i < size; i++)
    {
        cout << list[i] << endl;
    }



    return 0;
}

Answer 1

问题是在代码中处理size变量。

以下是更正后的代码。看到它工作here：

#include <iostream>
using namespace std;

const int CAP = 10;

int main()
{
    int size;
    int list[CAP] = { 12, 34, 45, 2, 8, 10, 16, 180, 182, 22 };
    size = CAP;
    int i, delIndex, addIndex, newInt = 0;

    cout << "Your list is: " << endl;
    for (i = 0; i < size; i++)
    {
        cout << list[i] << endl;
    } 

    //Deleting an index

    cout << "\nPlease enter index to delete from: ";
    cin >> delIndex;

    for (i = delIndex; i < size; i++)
    {
        list[i] = list[i + 1];
    }
    size--;
    cout << "The index position you specified has been deleted." << endl;
    cout << "The new array is: " << endl;
    for (i = 0; i < size; i++)
    {
        cout << list[i] << endl;
    }

    //Adding an index

    cout << "\nNow, please enter the index position to add to: " << endl;
    cin >> addIndex;
    cout << "\nEnter the number to add to the index: " << endl;
    cin >> newInt;

    for (i = size - 1; i >= addIndex; i--)
    {
        list[i + 1] = list[i];
    }
    list[addIndex] = newInt;
    size++;

    cout << "The number has been added at the specified index position." <<endl;
    cout << "The new array is: " << endl;
    for (i = 0; i < size; i++)
    {
        cout << list[i] << endl;
    }
    return 0;
}

注意：由于我们在讨论索引而不是数组中的位置，因此它被视为基于0，元素在索引addIndex处添加，而不是在addIndex-1。

Answer 2

你的程序中有一些漏洞，你可以改进。

1. 您正在声明一个常量（CAP），但数组大小正在发生变化，所以请点这样做。
2. 您正在多次打印数组，最好使用一个函数，并在每次需要打印整个数组时调用它。
3. 你在程序的某些部分使用像10这样的文字。建议使用相同的变量，如size或CAP而不是10来提高可读性。
4. 您甚至可以在函数中插入和删除它们，以便可以多次调用它们。

这是一个示例工作代码，您可以理解这一点。我没有实施第4步，我希望你能轻易做到，

LIVE CODE

工作守则

//This program demos basic arrays
#include <iostream>
using namespace std;
int CAP = 10;

void printArr(int list[]){
    for (int i = 0; i < CAP; i++)
        cout << list[i] << " ";
    cout<<endl;
}

int main()
{
    int list[CAP] = { 12, 34, 45, 2, 8, 10, 16, 180, 182, 22 };
    int i, delIndex, addIndex, newInt = 0;
    cout << "Your list is: " << endl;
    printArr(list);

    //Deleting an index
    cout << "\nPlease enter index(0 indexed based) to delete from: ";
    cin >> delIndex;
    for (i = delIndex; i < CAP - 1; i++)
        list[i] = list[i + 1];
    CAP--;
    cout << "The index position you specified has been deleted." << endl;
    cout << "The new array is: " << endl;
    printArr(list);

    //Adding an index
    cout << "\nNow, please enter the index position(0 indexed based) to add to: " << endl;
    cin >> addIndex;
    cout << "\nEnter the number to add to the index: " << endl;
    cin >> newInt;
    for (i = CAP; i > addIndex; i--)
        list[i] = list[i-1];        
    list[addIndex] = newInt;
    CAP++;
    cout << "The number has been added at the specified index position." << endl;
    cout << "The new array is: " << endl;
    printArr(list);
    return 0;
}