C++ Tutorial/File Stream/Text file write

file output with characters

<source lang="cpp">#include <fstream>

 #include <iostream>  
 #include <string>  
 using namespace std;  
   
 int main(){  
    string str = "AAA";  
   
    ofstream outfile("TEST.TXT");
    for(int j=0; j<str.size(); j++)
       outfile.put( str[j] );      
    cout << "File written\n";  
    return 0;  
 }</source>

file output with strings

<source lang="cpp">#include <fstream>

 using namespace std;  
   
 int main(){  
    ofstream outfile("TEST.TXT");  
                                   
    outfile << "test\n";  
    outfile << "1\n";  
    outfile << "2\n";  
    outfile << "3\n";  
    return 0;  
 }</source>

Output a text file character by character

<source lang="cpp">#include <iostream>

1. include <fstream>

using namespace std; int main(void){

  ifstream in("test.cpp");
  if(!in){
     cout << "Cannot open file." << endl;
     exit (1);
  }
  in.ignore(10, " ");
  char c;
  while(in)
  {
    in.get(c);
    cout << c;
  }
  in.close();

}</source>

Output string and decimal in hexadecimal format to a file with ostrstream

<source lang="cpp">#include <strstream>

1. include <iostream>

using namespace std; main() {

 char str[80];   
 int a = 10;   
    
 ostrstream outs(str, sizeof(str));   
    
 outs << "Hello there ";   
 outs << a+44 << hex << " ";   
 outs.setf(ios::showbase);   
 outs << 100 << ends;   
    
 cout << str;
    
 return 0;   

}</source>

Output to file line by line

<source lang="cpp">#include <fstream.H>

int main () {

 ofstream myfile("test.txt");
 if (myfile.is_open())
 {
   myfile << "This outputting a line.\n";
   myfile << "this is another line.\n";
   myfile.close();
 }
 return 0;

}</source>

Save string double pair to file

<source lang="cpp">#include <iostream>

1. include <fstream>

using namespace std; int main() {

 ofstream out("test.txt"); // output, normal file
 if(!out) {
   cout << "Cannot open test.txt file.\n";
   return 1;
 }
 out << "R " << 9.9 << endl;
 out << "T " << 9.9 << endl;
 out << "M " << 4.8 << endl;
 out.close();
 return 0;

}</source>

Use ofstream to write text to a file

<source lang="cpp">#include <iostream>

1. include <fstream>

using namespace std; main(void) {

 char *p = "hello there";   
    
 ofstream out("test");   
 if(!out) {   
   cout << "Cannot open file";   
   return 1;   
  }   
    
 while(*p) out.put(*p++);   
    
 out.close();   
    
 return 0;   

}</source>

Use put() to write to a file

<source lang="cpp">#include <iostream>

1. include <fstream>

using namespace std;

int main() {

 char *p = "hello\n"; 

 ofstream out("test", ios::out | ios::binary); 
 if(!out) { 
   cout << "Cannot open file.\n"; 
   return 1; 
  } 

 // Write characters until the null-terminator is reached. 
 while(*p) 
    out.put(*p++); 

 out.close(); 

 return 0; 

}</source>

Write formatted output to a text file.

<source lang="cpp">#include <iostream>

1. include <fstream>

using namespace std; int main() {

 ofstream fout("test.dat");
 if(!fout) {
   cout << "Cannot open file.\n";
   return 1;
 }
 fout << 10 << " " << -20 << " " << 30.2 << "\n";
 fout << "This is a test.";
 fout.close();
 if(!fout.good()) {
   cout << "A file error occurred.";
   return 1;
 }

}</source>

Write to file

<source lang="cpp">#include <iostream>

1. include <fstream>

using namespace std;

int main() {

 ofstream out("test.txt"); 
 if(!out) { 
   cout << "Cannot open file.\n"; 
   return 1; 
 } 

 out << 10 << " " << 123.23 << "\n"; 
 out << "This is a text."; 

 out.close(); 

 return 0; 

}</source>