fstream in c 2b 2b

1// basic file operations
2#include <iostream>
3#include <fstream>
4using namespace std;
5
6int main () {
7  ofstream myfile;
8  myfile.open ("example.txt");
9  myfile << "Writing this to a file.\n";
10  myfile.close();
11  return 0;
12}

1#include<fstream>
2int main()
3{
4  fstream file; 
5  /*if we use fstream then we need to specify at least one 
6  parameter mode like ios::out or ios::in else the file will not open */  
7  file.open("filename.txt", ios::out|ios::in);
8  /*all work with file*/
9  file.close();
10  return 0;
11}

1// io/read-file-sum.cpp - Read integers from file and print sum.
2// Fred Swartz 2003-08-20
3
4#include <iostream>
5#include <iomanip>
6#include <fstream>
7using namespace std;
8
9int main() {
10    int sum = 0;
11    int x;
12    ifstream inFile;
13    
14    inFile.open("test.txt");
15    if (!inFile) {
16        cout << "Unable to open file";
17        exit(1); // terminate with error
18    }
19    
20    while (inFile >> x) {
21        sum = sum + x;
22    }
23    
24    inFile.close();
25    cout << "Sum = " << sum << endl; 
26    return 0;
27}
28

1ofstream myfile;
2myfile.open("file.txt");
3
4myfile << "write this to file"