I tried to save some strings in csv file but it gets distorted [duplicate]

Question

this is my code it gets an string from user via cin and opens a file and appends it to the file resembeling a simple phonebook. what am I missing ? where am I going wrong? by the way I am using code blocks.

the phoneook.csv opened with notepad

#include <iostream>
#include <stdio.h>
#include <string.h>
using std::cin;
using std::cout;
using std::string;
using std::endl;

int main()
{
    string name;
    string number;
    cout << "Name: " ;
    cin >>  name ;
    cout << "Number: " ;
    cin >>  number;
    cout << name <<","<< number<<endl ;
    FILE *file = fopen ("phonebook.csv","a");
    if (file == NULL)
    {
        return 1;
    }
    fprintf (file , "%s,%s\n",name,number);
    fclose (file);
    return 0;
}

I checked the code by chenging string to integers and it worked. Thats why you see a number in the picture.

Do not post images of text and provide a minimal reproducible example. — Passer By
– Passer By, Commented Aug 30, 2024 at 6:47
%s is expecting a C string, you are passing a different type - C++ string. Either use C++ file API or name.c_str(). Also enable compiler warnings to catch this error at compile time. — Quimby
– Quimby, Commented Aug 30, 2024 at 6:49
Also paste your csv output in your question don't link to it. Side note : Where are you learning C++ from, that is still teaching you to use a "C" FILE pointer? This is C++ so at least use std::ofstream, which works much better with all the other C++ types like std::string — Pepijn Kramer
– Pepijn Kramer, Commented Aug 30, 2024 at 6:50
You're using C functions that have no knowledge about C++ objects. What resource are you using to learn C++? — Some programmer dude
– Some programmer dude, Commented Aug 30, 2024 at 6:57
fprintf (file , "%s,%s\n",name,number); this is wrong - this C API i unable to handle C++ types. Enable warnings as errors and compiler will tell you. Use C++ std::ofstream to avoid this problem. — Marek R
– Marek R, Commented Aug 30, 2024 at 6:59

john · Accepted Answer · 2024-08-30 07:06:07Z

1

You are mixing C and C++.

Either do it like this

fprintf (file , "%s,%s\n",name.c_str(),number.c_str());

c_str() converts a C++ string into the C string that fprintf expects.

But better (and simpler) would be to use pure C++ for your file output.

#include <fstream> // for ofstream

std::ofstream file("phonebook.csv", std::ios_base:app);
if (!file.is_open())
{
    return 1;
}
file << name << ',' << number << '\n';

This way you can use the << that you are already used to from std::cout for file output as well, instead of having to learn a whole new fprintf function.

answered Aug 30, 2024 at 7:06

john

88.3k5 gold badges61 silver badges95 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

I tried to save some strings in csv file but it gets distorted [duplicate]

1 Answer 1

Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Linked

Related