Reading Files in C Program. This is possible using stream extraction operator (>>). Expected Output : 10. Write a program in C to read an existing file. Test Data : Input the file name to be opened : test.txt C program to compare two files. Write a program in C to find the content of the file and number of lines in a Text File. Go to the editor. Advantages of "const"s are that they can be scoped, and they can be used in situations where a pointer to an object needs to be passed. Test Data : Write a program in C to decrypt a previously encrypted file file. 2. ofstream test line 3 You can find all the code examples and the input file at the GitHub repo for this article. Write a program in C to write multiple lines in a text file. Now, we will read a source file character by character and at the same time, we will write this character into the destination file. Go to the editor If the file opening is successful, then it returns a pointer to the file, and if it's unable to open it, then it returns NULL. Function fopen is used to open a file; it returns a pointer to structure FILE, which is a predefined structure in the "stdio.h" header file. Reading from a File; Close a File; File Handling In C++. Input the file name to be opened : test.txt Follow the steps to read the file: Create a file pointer. It also has the advantage that it has no type, so it can be used for any integer value without generating warnings. Allow both read and write operations to this file. opening file"); // exit from program if file pointer returns NULL. Expected Output : 6. test line 5 Write a program in C to encrypt a text file. It also has the advantage that it has no type, so it can be used for any integer value without generating warnings. #include #include // for exit() function int main() { char c[1000]; FILE *fptr; if ((fptr = fopen("studytonight.txt", "r")) == NULL) { printf("Error! Input the file name to be opened : test.txt Test Data : A successful read () updates the access time for the file. Expected Output : Now, if you read the file test.txt you will see the following : 15. an existing file with the last line not terminated by a newline character (could be considered being an invalid file format, since lines mostly are considered to be newline-terminated, not newline-separated). The main advantage to a #define is that it requires no memory to store in your program, as it is really just replacing some text with a literal value. If the file previously exits, add the information of n students. Let's say you have prepared your final project report. Test Data : Input the number of lines to be Go to the editor Home Solved C++ Programs C++ File Handling Programs C++ program to write and read text in/from file In this program, we will create a file and then write some text into then file , after writing text file will be closed and again file will open in read mode, read all written text. r+ Open an existing file. fseek () Sets the position of a file pointer to a specified location. Input the file name to be opened : test.txt Input the line no you want to replace : 2 Reading a file line by line is a trivial problem in many programming languages, but not in C. The standard way of reading a line of text in C is to use the fgets function, which is fine if you know in advance how long a line of text could be. C program to create a file and write data into file. . } close (): It is used to close an existing file. C program to read a file and print its content. Expected Output : Here is the content of the merge file mergefiles.txt : 13. getw () Reads an integer from a file. 1. For opening a text file; Start; Declare variable and file pointer; Assign file pointer to fopen() function with write format; If file is not opened, print error message; Else give the content using loop; Close the file; Stop; For Reading a Text File Files are used to store data in a storage device permanently. Write a program in C to read an existing file. File cannot be opened. The report spans across numerous . Test Data : Input the 2nd file name : test1.txt Input the file name to be opened : test.txt Write a program in C to read the file and store the lines into an array. Scala Programming Exercises, Practice, Solution. :: The lines are :: General functions used for File handling. The Write a text file (example 1) and the Write a text file (example 2) sections describe how to use the StreamWriter class to write text to a file. Input a sentence for the file : This is the content of the file test.txt. close(): To close an existing file. 1. fstream ifstream (Input Stream) is a class that is used to obtain input from any file. test line 1 Scala Programming Exercises, Practice, Solution. Expected Output : 7. . Write a program in C to append multiple lines at the end of a text file. File Input and Output in C . write (): It is used to write data into a file. Both the functions performed the same operations as that of scanf and gets but with an additional parameter, the file pointer. Next: Write a program in C to write multiple lines in a text file. Input the name of file to decrypt : test.txt 1) Create a variable to represent the file. Test Data : test line 6 Go to the editor. Input the 1st file name : test.txt In order to read information from a file, or to write information to a file, your program must take the following actions. Input the source file name : test.txt As we are well aware that C++ is one of the most widely used languages and it provides many features that allows the programmer to perform multiple tasks easily. 2) Open the file and store this "file" with the file variable. Test Data : Expected Output : 3. In order to read or write to a file, we must first open the file using the function fopen (). read (): It is used to read data from a file. A stream is an abstraction that represents a device on which operations of input and output are performed. open(): To create a file. Contribute your code (and comments) through Disqus. You can read information from files into your C++ program. Test Data : . #include #include void main() { FILE *fptr; char fname[20]; char str; printf("\n\n Read an existing file :\n"); printf("-----\n"); printf(" Input the filename to be opened : "); scanf("%s",fname); fptr = fopen (fname, "r"); if (fptr == NULL) { printf(" File does not exist or cannot be opened.\n"); exit(0); } printf("\n The content of the file %s is :\n",fname); str = fgetc(fptr); while (str != ftell () Returns the current position of a file pointer. Go to the editor. Now, we will read the contents of the file and then print those on the screen. test line 4 This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. Test Data : If my question is not correct, please comment and I will clear it. #include #include // For exit () function int main() { char c [1000]; FILE *fptr; if ( (fptr = fopen ("program.txt", "r")) == NULL) { printf("Error! This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. Write a program in C to delete a specific line from a file. Input the name of file to delete : test.txt C Program to Read content of a File and Display it Below is a simple program to read the content of any file and then print it on the output screen. Expected Output : Do not submit any solution of the above exercises at here, if you want to contribute go to the appropriate exercise page. Expected Output : 4. Test Data : File handling is one of the most important parts of programming. "); // Program exits if the file pointer returns NULL. Input the name of file to encrypt : test.txt The fread function generally used for binary file to read the binary data from the given file stream. You use the operator in the same way you use it to read user input from the keyboard. Program to read the first line from a file. Input the line you want to remove : 2 Classes for Reading/Writing Files In C++, three major files are used for interacting with files. Go to the editor Also read: Program in C to Replace Capital C with Capital S in a File. What is the difficulty level of this exercise? Go to the editor Write a program in C to write multiple lines in a text file. Input the new file name where to merge the above two files : mergefiles.txt I have to write with in a existing file put (): It is used to write a single character in the file. Definition of C++ Read File. Now see this program to copy one file get (): It is used to read a single character from the file. Close the file. This class extracts the contents from the file. C Program Before reading the file using programming, just create a text file in the current directory and add some text in a file using simple notepad. Expected Output : If you read the file test.txt you will see the following : 14. Input the content of the new line : Yes, I am the new text instead of test line 2 Previous: Write a program in C to create and store information in a text file. However, instead of using the cin object, you use the ifstream/ fstream object. In C, we use a structure pointer of a file type to declare a file: FILE *fp; C provides a number of build-in function to perform basic file operations: fopen() - create a new file or open a existing file; fclose() - close a file; getc() - reads a character from a file Writes a single character to a file. for each element, fgetc is called size times (count of bytes for a single element) and file position indicator for the stream is advanced by the number of characters read. I am trying to write "File opened" in a existing test.txt file with C program. exit(1); } // reads text until newline is encountered fscanf(fptr, "% [^\n]", c); printf("Data from the file:\n%s", c); fclose (fptr); return 0; } Write a program in C to Find the Number of Lines in a Text File. Reading from a file The file read operations can be performed using functions fscanf or fgets. Test Data : Go to the editor Write a C program to read name and marks of n number of students from user and store them in a file. Go to the editor The main advantage to a #define is that it requires no memory to store in your program, as it is really just replacing some text with a literal value. Write a program in C to create and store information in a text file. How to Read/ Write (I/O) Strings in Files fgets & fputs Create a new file and write to it. Write a program in C to replace a specific line with another text in a file. After this reading and writing, we will close both files. When we open the file in read mode, the file is first searched for in the disk and then loaded into the buffer. We open the file in r or read mode which allows us to read the contents of the file. The algorithm for opening and reading a text file in C has given below: Algorithm for Opening and Reading the text file. read: From the file indicated by the file descriptor fd, the read () function reads cnt bytes of input into the memory area indicated by buf. It is declared in stdio.h and takes four arguments. Write the file. Write a program in C to copy a file in another name. Have another way to solve this solution? test line 7 Input the new file name : test1.txt Test Data : struct food { int no; string name; float cost; }s; //TO read from file void read () { fstream f; f.open ("Existingfile.txt",ios::in); while (!f.eof ()) { f.read ( (char*)&s,sizeof (s)); . Syntax in C language size_t read (int fd, void* buf, size_t cnt); Test Data : C program to copy contents from one file to another file. Go to the editor Expected Output : 5. Is it better to use static const vars than #define preprocessor? But I must not create a test.txt file with the program. Expected Output : If you read the new file you will see the content of the file : 12. The function fscanf () permits to read and parse data from a file We can read (using the getc function) an entire file by looping to cover all the file until the EOF is encountered We can write to a file after creating its name, by using the function fprintf () and it must have the newline character at the end of the string text. Expected Output : 11. C program to read and merge two files in single file. a Append to the end of a file. f.close (); } P.S: I am new to stackoverflow. Advantages of "const"s are that they can be scoped, and they can be used in situations where a pointer to an object needs to be passed. File handling provides a mechanism to store the output of a program in a file and to perform various operations on it. Input the number of lines to be written : 3 Input the file name to be opened : test.txt a file with content that is opened by another process for reading; a file with content that is opened by another process for writing Go to the editor Expected Output : 8. open (): It is used to create and open a file. C program to read a file and display its contents - Codeforwin Write a program in C to remove a file from the disk. putw () Writing an integer to a file. Go to the editor. Go to the editor. Input the number of lines to be written : 4 . Input/output with files C++ provides the following classes to perform output and input of characters to/from files: ofstream: Stream class to write on files; ifstream: Stream class to read from files; fstream: Stream class to both read and write from/to files. Write a program in C to count a number of words and characters in a file. In C++, working on file operations is as easy as working normally on Is it better to use static const vars than #define preprocessor? After that, fscanf function will read the contents of the file and printf function will display the contents of the file on the screen. For that, we will first open the file in read mode using fopen function. Read a text file. Write a program in C to merge two files and write it in a new file. Test Data : If a file with the same name already exists, overwrite it rather, erase the existing file and create a new one. In simplest words, we can say that in order to read data from a file we use ifstream class. Go to the editor. The Read a text file section of this article describes how to use the StreamReader class to read a text file. Test Data : Input the filen ame to be opened : test.txt Expected Output : 2. Input the file name to be opened : test.txt Test Data : Go to the editor. If the file does not exist, create a new one and write to it. Expected Output : 9. test line 2 The lines are :