How to Read Numeric Data from a Text File Using C ?

Accessing Numeric Data from a Text File Using C

In this era of digital information, it often becomes necessary to extract numerical data from text files. This article will guide you through the process of reading and assigning numerical data from a text file to variables in C programming language.

Scenario

Consider a text file where the data is arranged as follows:

45.78   67.90   87
34.89   346     0.98

Your goal is to read this text file and assign each number to a respective variable in C .

Initial Approach

Your initial approach of using ifstream to open the text file is correct. However, to read multiple numbers separated by spaces, you need to use the >> operator repeatedly.

Modified Code

To read the numbers effectively, you can employ the following modified code:

#include <iostream>
#include <fstream>

using namespace std;

int main() {
  float a, b, c;
  ifstream myfile("data.txt");
  if (myfile.is_open()) {
    myfile >> a >> b >> c;
    cout << "First number: " << a << endl;
    cout << "Second number: " << b << endl;
    cout << "Third number: " << c << endl;
    myfile.close();
  } else {
    cout << "Error opening file" << endl;
  }
  return 0;
}

This code opens the text file, reads the first three numbers sequentially, and assigns them to the variables a, b, and c. You can expand this to accommodate more numbers as needed.

Alternative Approach for Reading Multiple Lines

If your text file contains multiple lines of numerical data, you can use a loop to read the numbers in each line and store them in an array or a vector.

Conclusion

This discussion has provided you with the necessary guidance to read numeric data from a text file and assign it to variables in C . By understanding the techniques presented here, you can effectively process numerical information in your C code.

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