ifstream

问题 This question already has an answer here : No matching function - ifstream open() (1 answer) Closed 5 years ago . I'm learning C++ and i'm getting some troubles when i'm trying to use a String in a ifstream method, like this: string filename; cout << "Enter the name of the file: "; cin >> filename; ifstream file ( filename ); Here is the full code: // obtaining file size #include <iostream> #include <fstream> using namespace std; int main ( int argc, char** argv ) { string file; long begin

问题 I want the user to give me the full path where the file exists and not just the file name. How do I open the file this way? Is it something like this: ifstream file; file.open("C:/Demo.txt", ios::in); This doesn't seem to work. 回答1: Normally one uses the backslash character as the path separator in Windows. So: ifstream file; file.open("C:\\Demo.txt", ios::in); Keep in mind that when written in C++ source code, you must use the double backslash because the backslash character itself means

问题 I just started using Visual Studio 2019 after using XCode for a while. I was always able to open txt files in XCode but now I can't open them in Visual Studio 2019. Basically what I do is I press "Start Without Debugging" in the "Debug" tab I and get the error message "File Did Not Open!" from the else statement that I wrote. I am not sure if it has something to do with where the txt file is located or with the file path. Below is the simple program that I've so far been using to figure out

问题 I just started using Visual Studio 2019 after using XCode for a while. I was always able to open txt files in XCode but now I can't open them in Visual Studio 2019. Basically what I do is I press "Start Without Debugging" in the "Debug" tab I and get the error message "File Did Not Open!" from the else statement that I wrote. I am not sure if it has something to do with where the txt file is located or with the file path. Below is the simple program that I've so far been using to figure out

问题 I am trying to read a .txt file line by line: vector<vector<int>> iVecGrid; vector<int> iVecRow; ifstream text; text.open("grid.txt", ios::in); if (!text) { cout << "Error!\n"; return EXIT_FAILURE; } istringstream isLine; string sLine; while (getline(text, sLine)) { isLine.str(sLine); int iNumber; while (isLine >> iNumber) { cout << iNumber << " "; iVecRow.push_back(iNumber); } cout << endl; iVecGrid.push_back(iVecRow); iVecRow.clear(); } When I put isLine inside the while (getline(text,

问题 I have the following c++ code by which I am reading values from .txt file Could you please help me to improve the code such that I can read not only 14 values but n values from the .txt //reading from text file static std::vector<double> vec; double a[14]; //values got read from txt file int i = 0; void readDATA() { double value; std::ifstream myFile; myFile.open("filename.txt", std::ios::app); if (myFile.is_open()) { std::cout << "File is open." << std::endl; while (myFile >> value) { vec

问题 I was reading Constructing a vector with istream_iterators which is about reading a complete file contents into a vector of chars. While I want a portion of a file to be loaded in to a vector of chars. #include <iostream> #include <fstream> #include <iterator> #include <vector> #include <algorithm> using namespace std; int main(int argc, char *argv[]) { ifstream ifs(argv[1], ios::binary); istreambuf_iterator<char> beginItr(ifs); istreambuf_iterator<char> endItr(beginItr); advance(endItr, 4);

问题 Could you please help in modifying the following code to add two things: having the ability to assign manual(default) value to a[i] if i was not available in the .txt file (e.g. first line in text file is 0, 0, 40, , 15 the forth element in nothing and in this case I want to assign it manually in the code to be for instance 70). letting the code read not only numbers but also strings (dealing with numbers and strings for example 0,0,8,"turn_right",4 ) struct Number { double value; operator

来源： https://stackoverflow.com/questions/64598494/getline-ifstream-failure

来源： https://stackoverflow.com/questions/64598494/getline-ifstream-failure