Reading and Writing Arrays to and from Files in C++
To read and write arrays to and from files in C++, we can use the file streams from the standard library, std::ifstream
for reading from files and std::ofstream
for writing to files. We can read and write the arrays in a similar way as any other data.
C++ Program to Read and Write Arrays to and from Files
The below example demonstrates how to read and write arrays to/from files in C++.
C++
// C++ program to demonstrate how to read and write arrays to/from files #include <fstream> #include <iostream> using namespace std; int main() { // Creating an array of size 5 int arr[] = { 1, 2, 3, 4, 5 }; int size = sizeof (arr) / sizeof (arr[0]); // Opening the file in write mode ofstream outfile( "array.txt" ); if (!outfile.is_open()) { cerr << "Failed to open file for writing.\n" ; return 1; } // Writing the array elements to the file for ( int i = 0; i < size; ++i) { outfile << arr[i] << " " ; } // Closing the file outfile.close(); // Opening the file in read mode ifstream infile( "array.txt" ); // Reading the array elements from the file for ( int i = 0; i < size; ++i) { infile >> arr[i]; } // Closing the file infile.close(); // Displaying the array elements cout << "Array elements: " ; for ( int i = 0; i < 5; ++i) { cout << arr[i] << " " ; } cout << endl; return 0; } |
Output
Array elements: 1 2 3 4 5
Time Complexity: O(N), here N is the size of the array.
Auxiliary Space: O(1)
How to Read and Write Arrays to/from Files in C++?
In C++, an array is a collection of elements of the same type placed in contiguous memory locations. A file is a container in a computer system for storing information. In this article, we will learn how to read and write arrays to/from files in C++.
Example:
Input:
Array = {1, 2, 3, 4, 5}
Output:
// Write the array to a file, then read the array from the file
Array: 1 2 3 4 5
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