Point 1: You cannot open to read if the file doesn’t exist. Fortunately you probably don’t want to. Simultaneously reading and writing the same file is problematic and almost always a bad idea. Until you know you have to read and write at the same time, open the file for reading read in the file … Read more
If you mean std::basic_stream::getline(), you provide a pointer to character array and the size of that array. You have to create the array somewhere by yourself. If some line is longer than sz – 1, only part of it with length sz – 1 will be read. If you don’t know the maximum length of … Read more
doing while (fin >> name >> var1 >> var2 >> var3) { cout << name << var1 << var2 << var3 << endl; } you rewrite all the time on the same variables, you need to put the value in a vector as you say in your question you need also to check if each … Read more
Try something more like this: cout << “Please enter a number to search: “; cin >> n; out << endl; out << “Occasions during the year when there were three consecutive days where the temperature went above ” << n << ” are:” << endl; int firstday, numdays = 0; for (int x = 0; … Read more
You can use the constructor to specify the filename: ifstream inputFile(“data.txt”); See the details for std::basic_ifstream (constructor). explicit basic_ifstream( const char* filename, std::ios_base::openmode mode = ios_base::in ); First, performs the same steps as the default constructor, then associates the stream with a file by calling rdbuf()->open(filename, mode | std::ios_base::in) (see std::basic_filebuf::open for the details on … Read more
If checking the username fails you still have extra data on that line that hasn’t been read in yet. Consider if the input data was the following username1;password username2;password When you read the first line and the username does not match you have password dangling on the current input line. So now your input looks … Read more
C++11 introduces the new header system_error for low level errors. It is possible to write your own error categories. This might be good starting point for writing your own error handling in modern C++. 7 solved c++ std::exception … may I have more please? [closed]
You can’t. Files don’t really have lines, they just store a bunch of characters/binary data. When you have 1,2,3,4,5 6,7,8,9,0 It only looks that was because there is an invisible character in there that tells it to write the second line to the second line. The actual data in the file is 1,2,3,4,5\n6,7,8,9,0 So you … Read more
You can’t copy a C string using assignment to the pointer, you need to use strcpy(). void setname(string n) { if (n.size() >= sizeof name) { cout << “Name ” << n << ” is too long\n”; } else { strcpy(name, n.c_str()); } } Also, ptr = &name[30]; is a pointer to beyond the end … Read more
Simply: #include <fstream> #include <iostream> int main() { std::fstream file(“table1.txt”); std::string word; while (file >> word) { // do whatever you want, e.g. print: std::cout << word << std::endl; } file.close(); return 0; } word variable will contain every single word from a text file (words should be separated by space in your file). 1 … Read more
you forgot to add ‘\0’ char in zero terminated char array, after you replaced value with index 2. 1 solved Assigning char array from ifstream breaks array if adding another char to array