如何在C ++中移动2个dim数组 [英] How to shift 2 dim array in C++

问题描述

hii

如何移动2个昏暗阵列

它是用于课程和成绩的数组，以及用户在程序开头输入的数组大小。

我也有一个名字的字符串数组。

如果它是4门课程将是这样的：

名称等级1等级2等级3等级4

i想要删除一行然后移动所以最后一行将为零。

i将向您显示所有移动的部分，我尝试了但是它没有工作，当我输入名称时光标没有做任何事情：



我尝试过：

hii
how can i shift 2 dim array
it's array for courses and grades , and the size of the array entered by the user at the beginning of the program.
also i have a string array for names.
it will be like this if it's 4 courses :
name grade1 grade2 grade3 grade4
i want to delete a row and then shift so the last row will be zero.
i will show you all only the part of shifting, what i have tried but it didn't work, when i enter the name the cursor goes down without doing anything :

What I have tried:

index=0;
	cout<<"Enter your name :";
	cin>>name;
for(int p=0;p<i;p++){
   if (arn[p]==name)
    index=p;}

for(int row=index;row<i;row++){
  for (int colm1=0;colm1<j;colm1++)
  	arcg[row][colm1]=arcg[row-1][colm1-1];}
  	
  	for(int colm2=0;colm2<j;colm2++)
  	arcg[i-1][colm2]=0;

    for (int row3=0;row3<i;i++) {
    	if (arn[row3]==name)
    	arn[row3]=arn[row3+1];
    	arn[i-1]="0";}
    	
    	for(int row=0;row<i;row++){
  for (int colm1=0;colm1<j;colm1++){
  	cout<<arcg[row][colm1]<<"/t";
  }
  }
    for(int colm2=0;colm2<j;colm2++){
    	cout<<arn[colm2]<<"/t";
	}

推荐答案

你不会移动东西。创建一个新数组，将旧数组中的元素复制到新数组，跳过删除的项，销毁旧数组并返回新数组。

You don't move stuff around. Create a new array, copy the elements from the old array to the new one, skipping the items you deleted, destroy the old array and return the new array.

尝试

Try

#include <iostream>
#include <string>
using namespace std;
int main()
{
  string name;
  int index;
  cout << "Enter your name :";
  cin >> name;

  int i=3;
  int j=4;


  const int ROWS=i;
  const int COLS=j;

  string arn[ROWS] = {"foo", "boo", "goo"};
  int arcg[ROWS][COLS] = { { 0, 1, 2, 3}, {10, 11, 12, 13}, {20, 21, 22, 23}};

  index = ROWS;
  for(int p=0;p<ROWS;p++)
  {
    if (arn[p]==name)
    {
      index = p;
      break;
    }
  }

  // shift
  for ( int row = index; row<ROWS-1; ++row)
  {
    arn[row] = arn[row+1];
    for ( int col= 0; col < COLS; ++col)
      arcg[row][col] = arcg[row+1][col];
  }
  // reset last row
  if ( index != ROWS )
  {
    arn[ROWS-1] = "-";
    for ( int col= 0; col < COLS; ++col)
      arcg[ROWS-1][col] = 0;
  }

  // show the arrays
  for ( int row = 0; row<ROWS; ++row)
  {
    cout << arn[row];
    for ( int col= 0; col < COLS; ++col)
      cout << "\t" <<  arcg[row][col];
    cout << endl;
  }
}

请注意， C ++ （特别是现代 C ++ ）提供了更强大的工具：

Please note, C++ (expecially modern C++) offers far more powerful tools:

#include <iostream>
#include <unordered_map>
#include <array>
using namespace std;

int main()
{
  constexpr int COLS = 4;
  unordered_map < string, array < int, COLS > > m;

  m["foo"] = array<int,COLS>{0,1,2,3};
  m["boo"] = array<int,COLS>{10,11,12,13};
  m["goo"] = array<int,COLS>{20,21,22,23};

  string name;

  cout << "Enter your name: ";
  cin >> name;

  auto it = m.find(name);
  if (it != m.end())
    m.erase(it);

  for (const auto & p : m)
  {
    cout << p.first;
    for (const auto & i : p.second)
      cout << "\t" << i;
    cout << endl;
  }
}

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