C++ read file line by line

We can use the std::getline function to read the input line by line from a particular stream. We can redirect the getline to the file stream to read the file line by line. Skip to content.

When working on any operating system, files play a crucial role in the daily lives of programmers, computer users, and students. These files assist us in storing our data securely and redundantly in various formats. The first is to read the line token by token and the second is Line based on parsing, which is done using string streams that we get using the std::getline Function. When the delimiter char is reached, the function reads characters from the input stream and puts them in a string. After that the file we have created we will open it and add some content to it and then close the file using the close method. After that, we will again open the file and create a string sa and then using the getline function, we will read the entire file line by line and put the data into the string. After that, we printed the data, and at last, we closed the file.

C++ read file line by line

Nov 26, at am UTC. Last edited on Nov 26, at am UTC. That's kind of what you're doing, isn't it? Am I misunderstanding something, here? Also, it's better to loop on getline , and prefer std::string to C-style strings. The code which i posted is reading file. So how this can be implemented in loop reading line by line and passing one line once that line encounter end of line. That doesn't make overly sense. The for loop line 8 has no effect. Nov 26, at pm UTC.

Easy Normal Medium Hard Expert. It isn't clear why a for loop is used.

It is a library of container classes, algorithms, and iterators. Vectors are the same as dynamic arrays with the ability to resize themselves automatically when an element is inserted or deleted, with their storage being handled automatically by the container. In this article, we will see how to read lines into a vector and display each line. We will use File Handling concepts for this. Skip to content. Change Language.

Using file handling we can store our data in secondary memory Hard disk. Skip to content. Change Language. Open In App. Related Articles. Solve Coding Problems.

C++ read file line by line

While doing so, the goal was to handle all underlying stream errors as well as file opening errors, and to emit as precise error messages as possible. In a high-level programming language such as Python this level of reliability and usability is not difficult to obtain. Proper handling of the stream error bits eofbit , failbit , and badbit requires a tremendous amount of care, as discussed for example here , here , and here , and finally at cplusplus. It is worth mentioning that although cplusplus. When it comes to the idea of providing meaningful error messages, things become quite complicated. Proper evaluation of errno , respectively perror , in response to the stream error bits is not a trivial task as can be inferred from discussions like this and this. From these discussions we learn that most of the related uncertainty comes from a lack of centralized documentation or even missing documentation. We for example expect that when fopen returns NULL , errno is set to something meaningful. But where is this actually documented? In order to understand the relation between the language and operating system constructs involved, I performed quite some research and testing.

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Program to delete a line given the line number from a file. Report issue Report. The for loop line 8 has no effect. Hire With Us. That doesn't make overly sense. Still i am working on it.. Data Science. Get paid for your published articles and stand a chance to win tablet, smartwatch and exclusive GfG goodies! You'll be able to see the flow of control much more clearly, and see errors more easily. Also, even when a conditional block has a single line - e. Complete Tutorials. Contribute your expertise and make a difference in the GeeksforGeeks portal.

It is a library of container classes, algorithms, and iterators. Vectors are the same as dynamic arrays with the ability to resize themselves automatically when an element is inserted or deleted, with their storage being handled automatically by the container.

View More. It isn't clear why a for loop is used. Help us improve. Interview Experiences. Easy Normal Medium Hard Expert. Campus Experiences. Report issue Report. When the delimiter char is reached, the function reads characters from the input stream and puts them in a string. Change Language. Vote for difficulty :.