Merge pull request #11 from nawarajshah/file-handling

File handling

.gitignore

@@ -38,3 +38,5 @@ relative/path/to/dir/anotherfile
 
 # Ignore vscode files
 */.vscode/
+
+*.exe

FileHandling/README.md

@@ -0,0 +1,7 @@
+
+- [x] [q1](q1.cpp): WAP to open a file using constructor.
+- [x] [q2](q2.cpp): WAP to open a file using member function.
+- [x] [q3](q3.cpp): WAP to user r/w file using fstream.
+- [x] [q4](q4.cpp): WAP using fin and fout.
+- [x] [q5](q5.cpp): WAP to show use of manipulators.
+- [x] [q6](q6.cpp): WAP to store book database in a file. Design a book class with members ISBN number, name of author, title, price. The Program should able to store book object to a file, find a book in the database and display according to ISBN number. Also display all records.

FileHandling/q1.cpp

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+// WAP to open a file using constructor.
+
+#include <iostream>
+#include <fstream>
+
+class FileOpener {
+private:
+    std::ifstream file; // Input file stream
+
+public:
+    // Constructor that takes a filename as an argument and opens the file
+    FileOpener(const std::string& filename) {
+        file.open(filename, std::ios::in); // Open the file in read mode
+
+        if (!file) {
+            std::cerr << "Error opening file: " << filename << std::endl;
+            exit(1); // Exit the program if file opening fails
+        } else {
+            std::cout << "File " << filename << " opened successfully!" << std::endl;
+        }
+    }
+
+    // Destructor to close the file
+    ~FileOpener() {
+        if (file.is_open()) {
+            file.close();
+            std::cout << "File closed successfully!" << std::endl;
+        }
+    }
+};
+
+int main() {
+    std::string filename;
+
+    std::cout << "Enter the filename to open: ";
+    std::cin >> filename;
+
+    FileOpener fileOpener(filename); // This will open the file using the constructor
+
+    // Do any operations with the file here...
+
+    return 0; // File will be closed automatically when the object goes out of scope
+}

FileHandling/q2.cpp

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+// WAP to open a file using member function.
+
+#include <iostream>
+#include <fstream>
+
+class FileHandler {
+private:
+    std::ifstream file; // Input file stream
+
+public:
+    // Member function to open a file
+    void openFile(const std::string& filename) {
+        file.open(filename, std::ios::in); // Open the file in read mode
+
+        if (!file) {
+            std::cerr << "Error opening file: " << filename << std::endl;
+        } else {
+            std::cout << "File " << filename << " opened successfully!" << std::endl;
+        }
+    }
+
+    // Destructor to close the file
+    ~FileHandler() {
+        if (file.is_open()) {
+            file.close();
+            std::cout << "File closed successfully!" << std::endl;
+        }
+    }
+};
+
+int main() {
+    std::string filename;
+
+    std::cout << "Enter the filename to open: ";
+    std::cin >> filename;
+
+    FileHandler fileHandler;
+    fileHandler.openFile(filename); // This will open the file using the member function
+
+    // Do any operations with the file here...
+
+    return 0; // File will be closed automatically when the object goes out of scope
+}

FileHandling/q3.cpp

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+// WAP to user r/w file using fstream.
+
+#include <iostream>
+#include <fstream>
+#include <string>
+
+class FileHandler {
+private:
+    std::fstream file; // File stream for both reading and writing
+
+public:
+    // Member function to open a file in read/write mode
+    void openFile(const std::string& filename) {
+        file.open(filename, std::ios::in | std::ios::out | std::ios::app); // Open file in read/write mode, and append mode
+
+        if (!file) {
+            std::cerr << "Error opening file: " << filename << std::endl;
+            exit(1);
+        }
+    }
+
+    // Member function to write data to the file
+    void writeToFile(const std::string& data) {
+        file << data << std::endl;
+    }
+
+    // Member function to read data from the file
+    void readFromFile() {
+        std::string line;
+        while (getline(file, line)) {
+            std::cout << line << std::endl;
+        }
+    }
+
+    // Member function to reset the file pointer to the beginning
+    void resetFilePointer() {
+        file.seekg(0, std::ios::beg);
+    }
+
+    // Destructor to close the file
+    ~FileHandler() {
+        if (file.is_open()) {
+            file.close();
+        }
+    }
+};
+
+int main() {
+    FileHandler fileHandler;
+    fileHandler.openFile("sample.txt");
+
+    // Writing to the file
+    fileHandler.writeToFile("Hello, World!");
+
+    // Reset file pointer to the beginning for reading
+    fileHandler.resetFilePointer();
+
+    // Reading from the file
+    std::cout << "Contents of the file:" << std::endl;
+    fileHandler.readFromFile();
+
+    return 0;
+}

FileHandling/q4.cpp

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+// WAP using fin and fout.
+
+#include <iostream>
+#include <fstream>
+#include <string>
+
+class FileHandler {
+public:
+    // Member function to write data to the file using ofstream (fout)
+    void writeToFile(const std::string& filename, const std::string& data) {
+        std::ofstream fout(filename, std::ios::app); // Open file in append mode
+
+        if (!fout) {
+            std::cerr << "Error opening file for writing: " << filename << std::endl;
+            exit(1);
+        }
+
+        fout << data << std::endl;
+        fout.close();
+    }
+
+    // Member function to read data from the file using ifstream (fin)
+    void readFromFile(const std::string& filename) {
+        std::ifstream fin(filename); // Open file in read mode
+
+        if (!fin) {
+            std::cerr << "Error opening file for reading: " << filename << std::endl;
+            exit(1);
+        }
+
+        std::string line;
+        while (getline(fin, line)) {
+            std::cout << line << std::endl;
+        }
+
+        fin.close();
+    }
+};
+
+int main() {
+    FileHandler fileHandler;
+    std::string filename = "sample.txt";
+
+    // Writing to the file using fout
+    fileHandler.writeToFile(filename, "Hello, World!");
+
+    // Reading from the file using fin
+    std::cout << "Contents of the file:" << std::endl;
+    fileHandler.readFromFile(filename);
+
+    return 0;
+}

FileHandling/q5.cpp

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+// WAP to show use of manipulators.
+
+#include <iostream>
+#include <iomanip>  // Required for manipulators like setw, setprecision, etc.
+
+int main() {
+    int number = 12345;
+    double pi = 3.141592653589793;
+
+    std::cout << "Without setw:" << std::endl;
+    std::cout << number << std::endl;
+    std::cout << pi << std::endl;
+
+    std::cout << "\nWith setw:" << std::endl;
+    std::cout << std::setw(10) << number << std::endl;  // Right aligns the number with a width of 10
+    std::cout << std::setw(10) << pi << std::endl;      // Right aligns the value of pi with a width of 10
+
+    std::cout << "\nWith setprecision:" << std::endl;
+    std::cout << std::setprecision(5) << pi << std::endl; // Displays pi with a total of 5 digits
+    std::cout << std::setprecision(9) << pi << std::endl; // Displays pi with a total of 9 digits
+
+    std::cout << "\nWith fixed and setprecision:" << std::endl;
+    std::cout << std::fixed << std::setprecision(2) << pi << std::endl; // Displays pi with exactly 2 digits after the decimal point
+
+    std::cout << "\nWith showpos:" << std::endl;
+    std::cout << std::showpos << number << std::endl;  // Displays the positive sign before positive numbers
+
+    return 0;
+}