从.txt文件中读取并将值输入到多维向量中

初始化向量；矢量点；现在创建循环

for (int i = 0; i < hauteur; i++) {
    for (j = 0; j < largeur; j++) {
        int tmp;
        f_in >>tmp;
        points.push_back(tmp);
    }
}

它必须在上运行

这是一个完整的解决方案。我添加了很多评论来帮助你理解正在发生的一切。我们假设文件格式正确（即你给它正确的格式）。

使用它，颜色被存储在颜色矢量中，像素数据被存储在数据矢量中。我们浏览文件1次，读取所有我们想要的值。

您可能需要查找一些用于更好地理解它们的函数。http://www.cplusplus.com/reference/string/string/getline/http://www.cplusplus.com/reference/vector/vector/http://mathbits.com/MathBits/CompSci/APstrings/APgetline.htm（这就是为什么我们必须使用伪getline）

我还在末尾添加了一些打印，以便使用迭代器打印出数据。如果有什么不清楚的地方，请告诉我。

测试数据：

3
2
2
205
35
1
1
1
2
2
2

这是程序：

#include <iostream>
#include <fstream>
#include <string>
#include <vector>
using namespace std;
int main() {
  ifstream f_in;
  f_in.open("Pixmap.txt");
  //If its not open return with an error
  if (!f_in.is_open())
    cerr << "Error!";
  int width;
  int height;
  int numColours;
  //Read width and height and num of colours (first 3 lines from file)
  f_in >> width;
  f_in >> height;
  f_in >> numColours;
  vector<int> colours; //we will store the colours in here
  //Read in colours
  for (int c = 0; c < numColours; ++c) { //we have a loop that iterated numColours times
    int colour;
    f_in >> colour; //read in colour
    colours.push_back(colour); //push to the back of the vector so the read will be in order
  }
  //Make multidimentional vector
  //the data(height, vector<int>(width)) means we are initilizing the size of
  //of the inner vector. There are 'height' rows (ie height number of vector<int> and each
  //vector<int> is initilised to a vector<int>(width), ie vector<int> of size width
  //All the initial values will be 0
  vector<vector<int>> data(height, vector<int>(width));
  string input; //input string for reading lines
  int i = 0;
  int j = 0;
  //We need a dummy read so our stream points to the pixel data
  //We could do this in other ways but right now we will use getline to get a line but not save it
  //This is actually an issue with using >> operator before getline (see my link to read about it)
  getline(f_in, input);
  //We use getline in a loop like this. Get line will get 1 line from the file pointed to by the stream and store it
  //In the input string
  while (getline(f_in, input)) {
    data[i][j++] = stoi(input); //We store the data we need, stoi converts strings to integers
    //Once j has reached end of vector
    if (j == width) {
      ++i; //increase i (we are at a new row now)
      j = 0; //set j = 0, the width has been reached and we want to start at 0th spot on new line
    }
  }
  //Print out colours
  int colNum = 0;
  cout << "Num of Colours: " << numColours << endl;
  for (auto itc = colours.begin(); itc != colours.end(); ++itc) {
    cout << "Colour " << ++colNum << ": " << *itc << endl;
  }
  //Print out the vector
  for (auto it = data.begin(); it != data.end(); ++it) {
    for (auto it2 = it->begin(); it2 != it->end(); ++it2) {
      cout << *it2 << " ";
    }
    cout << endl;
  }
  //close stream
  f_in.close();
  return 0;
}