Task: Append a record to the end of a text file


C++: #include <iostream>
#include <fstream>
#include <string>
#include <vector>

std::ostream& operator<<(std::ostream& out, const std::string s) {
    return out << s.c_str();
}

struct gecos_t {
    std::string fullname, office, extension, homephone, email;

    friend std::ostream& operator<<(std::ostream&, const gecos_t&);
};

std::ostream& operator<<(std::ostream& out, const gecos_t& g) {
    return out << g.fullname << ',' << g.office << ',' << g.extension << ',' << g.homephone << ',' << g.email;
}

struct passwd_t {
    std::string account, password;
    int uid, gid;
    gecos_t gecos;
    std::string directory, shell;

    passwd_t(const std::string& a, const std::string& p, int u, int g, const gecos_t& ge, const std::string& d, const std::string& s)
        : account(a), password(p), uid(u), gid(g), gecos(ge), directory(d), shell(s)
    {
        
    }

    friend std::ostream& operator<<(std::ostream&, const passwd_t&);
};

std::ostream& operator<<(std::ostream& out, const passwd_t& p) {
    return out << p.account << ':' << p.password << ':' << p.uid << ':' << p.gid << ':' << p.gecos << ':' << p.directory << ':' << p.shell;
}

std::vector<passwd_t> passwd_list{
    {
        "jsmith", "x", 1001, 1000,
        {"Joe Smith", "Room 1007", "(234)555-8917", "(234)555-0077", "jsmith@rosettacode.org"},
        "/home/jsmith", "/bin/bash"
    },
    {
        "jdoe", "x", 1002, 1000,
        {"Jane Doe", "Room 1004", "(234)555-8914", "(234)555-0044", "jdoe@rosettacode.org"},
        "/home/jdoe", "/bin/bash"
    }
};

int main() {
    
    std::ofstream out_fd("passwd.txt");
    for (size_t i = 0; i < passwd_list.size(); ++i) {
        out_fd << passwd_list[i] << '\n';
    }
    out_fd.close();

    
    out_fd.open("passwd.txt", std::ios::app);
    out_fd << passwd_t("xyz", "x", 1003, 1000, { "X Yz", "Room 1003", "(234)555-8913", "(234)555-0033", "xyz@rosettacode.org" }, "/home/xyz", "/bin/bash") << '\n';
    out_fd.close();

    
    std::ifstream in_fd("passwd.txt");
    std::string line, temp;
    while (std::getline(in_fd, temp)) {
        
        if (!temp.empty()) {
            line = temp;
        }
    }
    if (line.substr(0, 4) == "xyz:") {
        std::cout << "Appended record: " << line << '\n';
    } else {
        std::cout << "Failed to find the expected record appended.\n";
    }

    return 0;
}









Fortran:       PROGRAM DEMO	
      TYPE DETAILS		
       CHARACTER*28 FULLNAME
       CHARACTER*12 OFFICE
       CHARACTER*16 EXTENSION
       CHARACTER*16 HOMEPHONE
       CHARACTER*88 EMAIL
      END TYPE DETAILS
      TYPE USERSTUFF		
       CHARACTER*8 ACCOUNT
       CHARACTER*8 PASSWORD	
       INTEGER*2 UID
       INTEGER*2 GID
       TYPE(DETAILS) PERSON
       CHARACTER*18 DIRECTORY
       CHARACTER*12 SHELL
      END TYPE USERSTUFF
      TYPE(USERSTUFF) NOTE	
      NAMELIST /STUFF/ NOTE	
      INTEGER F,MSG,N
      MSG = 6	
      F = 10	
      OPEN(MSG, DELIM = "QUOTE")	

Create the file and supply its initial content.
      OPEN (F, FILE="Staff.txt",STATUS="REPLACE",ACTION="WRITE",
     1 DELIM="QUOTE",RECL=666)	

      WRITE (F,*) USERSTUFF("jsmith","x",1001,1000,
     1 DETAILS("Joe Smith","Room 1007","(234)555-8917",
     2  "(234)555-0077","jsmith@rosettacode.org"),
     2 "/home/jsmith","/bin/bash")

      WRITE (F,*) USERSTUFF("jdoe","x",1002,1000,
     1 DETAILS("Jane Doe","Room 1004","(234)555-8914",
     2  "(234)555-0044","jdoe@rosettacode.org"),
     3 "home/jdoe","/bin/bash")
      CLOSE (F)		

Choose the existing file, and append a further record to it.
      OPEN (F, FILE="Staff.txt",STATUS="OLD",ACTION="WRITE",
     1 DELIM="QUOTE",RECL=666,ACCESS="APPEND")

      NOTE = USERSTUFF("xyz","x",1003,1000,		
     1 DETAILS("X Yz","Room 1003","(234)555-8193",
     2  "(234)555-033","xyz@rosettacode.org"),
     3 "/home/xyz","/bin/bash")
      WRITE (F,*) NOTE					
      CLOSE (F)

Chase through the file, revealing what had been written..
      OPEN (F, FILE="Staff.txt",STATUS="OLD",ACTION="READ",
     1 DELIM="QUOTE",RECL=666)
      N = 0
   10 READ (F,*,END = 20) NOTE	
      N = N + 1			
      WRITE (MSG,11) N		
   11 FORMAT (/,"Record ",I0)	
      WRITE (MSG,STUFF)		
      GO TO 10			

Closedown.
   20 CLOSE (F)
      END