Some problems in C++

[050449]

I started C++ two days ago and need your help

<br /> #include <iostream><br /> #include <fstream><br /> #include <string.h><br /> #include <string><br /> #include <stdio.h><br /> #include <stdlib.h><br /> <br /> <br /> using namespace std;<br /> char sendtext;<br /> char username;<br /> void read(){<br /> system("cls");<br /> cout << "You autorised as:" << username << "n";<br /> ifstream in;<br /> in.open("msngr.txt");<br /> if (!in) {<br /> cout << "Input file cannot be opened.n";<br /> //return(1);<br /> }<br /> char str[20000];<br /> while (!in.eof()) {<br /> in >> str;<br /> cout << str << "n";<br /> strcpy(str, "");<br /> }<br /> cout << "n";<br /> in.close();<br /> <br /> }<br /> void<br /> write(){<br /> <br /> cin >> sendtext;<br /> if(sendtext){<br /> FILE * pFile;<br /> char yazi[] = {sendtext , 'n'};<br /> pFile = fopen ( "msngr.txt" , "a+" );<br /> fwrite (yazi , 1 , sizeof(yazi) , pFile );<br /> fclose (pFile);<br /> read();<br /> write();<br /> }<br /> }<br /> main(){<br /> cout << "Enter your username: ";<br /> cin >> username;<br /> read();<br /> write();<br /> <br /> <br /> return (0);<br /> }<br /> <br /> </string></fstream></iostream>

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56

<br /> #include <iostream><br /> #include <fstream><br /> #include <string.h><br /> #include <string><br /> #include <stdio.h><br /> #include <stdlib.h><br /> <br /> <br /> using namespace std;<br /> char sendtext;<br /> char username;<br /> void read(){<br /> system("cls");<br /> cout << "You autorised as:" << username << "n";<br /> ifstream in;<br /> in.open("msngr.txt");<br /> if (!in) {<br /> cout << "Input file cannot be opened.n";<br /> //return(1);<br /> }<br /> char str[20000];<br /> while (!in.eof()) {<br /> in >> str;<br /> cout << str << "n";<br /> strcpy(str, "");<br /> }<br /> cout << "n";<br /> in.close();<br /> <br /> }<br /> void<br /> write(){<br /> <br /> cin >> sendtext;<br /> if(sendtext){<br /> FILE * pFile;<br /> char yazi[] = {sendtext , 'n'};<br /> pFile = fopen ( "msngr.txt" , "a+" );<br /> fwrite (yazi , 1 , sizeof(yazi) , pFile );<br /> fclose (pFile);<br /> read();<br /> write();<br /> }<br /> }<br /> main(){<br /> cout << "Enter your username: ";<br /> cin >> username;<br /> read();<br /> write();<br /> <br /> <br /> return (0);<br /> }<br /> <br /> </string></fstream></iostream>

why its not work properly? Please help.

[GWILouisaxwzkla]

The first function “read” looks ok to output the file data one word per line ,except I would probably pass the user’s name as a parameter instead of a global variable :

<br /> void read( char * userName );<br />

1 2 3

<br /> void read( char * userName );<br />

the second function for adding data to a file ( not sure why you used both fstream.h and stdio.h for file input / output in the same program ( ? ) ) seems to have some problems. First I would allocate an array of the proper size and use strcpy ( string.h ) to copy the data.

<br /> char yazi [ MAX_SIZE ];<br /> strcpy ( yazi , sendText );<br />

1 2 3 4

<br /> char yazi [ MAX_SIZE ];<br /> strcpy ( yazi , sendText );<br />

Next , you should take read() and write() out of the conditional or the program will never end :

<br /> if ( sendtext )<br /> {<br /> FILE * pFile;<br /> char yazi[] = {sendtext , 'n'};<br /> pFile = fopen ( "msngr.txt" , "a+" );<br /> fwrite (yazi , 1 , sizeof(yazi) , pFile );<br /> fclose (pFile);<br /> read(); //take these out!<br /> write();<br /> }<br /> <br />

1 2 3 4 5 6 7 8 9 10 11 12 13

<br /> if ( sendtext )<br /> {<br /> FILE * pFile;<br /> char yazi[] = {sendtext , 'n'};<br /> pFile = fopen ( "msngr.txt" , "a+" );<br /> fwrite (yazi , 1 , sizeof(yazi) , pFile );<br /> fclose (pFile);<br /> read(); //take these out!<br /> write();<br /> }<br /> <br />

thats what I see so far…..

[050449]

thanks for all but there is error

`MAX_SIZE’ undeclared (first use this function)

[050449]

thanks for all but there is error

`MAX_SIZE’ undeclared (first use this function)

[050449]

i defined MAX_SIZE and this problem solved but now it shows me

invalid conversion from char’ to const char*’
initializing argument 2 of `char* strcpy(char*, const char*)’

[050449]

if ( sendtext )
{
FILE * pFile;
char yazi[] = {sendtext , ‘n’};
pFile = fopen ( “msngr.txt” , “a+” );
fwrite (yazi , 1 , sizeof(yazi) , pFile );
fclose (pFile);
read(); //take these out!
write();
}

if i take this out my new text will not appear

[GWILouisaxwzkla]

for the write function I would do something like ( I don’t think I would have the console prompt inside the function , but if this is what you want ):

<br /> <br /> void write ()<br /> {<br /> <br /> char choice;<br /> cout << "do you want to input data to file ( y or n )" << endl;<br /> cin >> choice;<br /> cin.get(); //get newline<br /> while ( choice != 'y' &#038;& choice != 'n' )<br /> {<br /> cout << "bad choice!" << endl;<br /> cout << "do you want to input data to file ( y or n )" << endl;<br /> cin >> choice;<br /> cin.get(); //get newline<br /> }<br /> <br /> if ( choice == 'y' )<br /> {<br /> char inputText [ MAX_NAME ];<br /> cout << "enter input text: " << endl;<br /> cin.getline ( inputText , MAX_NAME , 'n' );<br /> <br /> ofstream outputFile;<br /> //PUT YOUR DATA FILE NAME HERE!<br /> outputFile.open ( "c:\programs\help\data3.txt" , ios::app );<br /> outputFile << inputText << endl;<br /> outputFile.close();<br /> <br /> }<br /> <br /> }<br />

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33

<br /> <br /> void write ()<br /> {<br /> <br /> char choice;<br /> cout << "do you want to input data to file ( y or n )" << endl;<br /> cin >> choice;<br /> cin.get(); //get newline<br /> while ( choice != 'y' &#038;& choice != 'n' )<br /> {<br /> cout << "bad choice!" << endl;<br /> cout << "do you want to input data to file ( y or n )" << endl;<br /> cin >> choice;<br /> cin.get(); //get newline<br /> }<br /> <br /> if ( choice == 'y' )<br /> {<br /> char inputText [ MAX_NAME ];<br /> cout << "enter input text: " << endl;<br /> cin.getline ( inputText , MAX_NAME , 'n' );<br /> <br /> ofstream outputFile;<br /> //PUT YOUR DATA FILE NAME HERE!<br /> outputFile.open ( "c:\programs\help\data3.txt" , ios::app );<br /> outputFile << inputText << endl;<br /> outputFile.close();<br /> <br /> }<br /> <br /> }<br />

[050449]

thanks it works ok.
now code is

<br /> #include <iostream><br /> #include <fstream><br /> #include <string.h><br /> #include <stdlib.h><br /> #define MAX_NAME 1000<br /> <br /> <br /> using namespace std;<br /> char sendtext;<br /> char username;<br /> <br /> void read(){<br /> system("cls");<br /> cout << "You autorised as:" << username << "n";<br /> ifstream in;<br /> in.open("msngr.txt");<br /> if (!in) {<br /> cout << "Input file cannot be opened.n";<br /> //return(1);<br /> }<br /> char str[20000];<br /> while (!in.eof()) {<br /> in >> str;<br /> cout << str << "n";<br /> strcpy(str, "");<br /> }<br /> cout << "n";<br /> in.close();<br /> <br /> }<br /> void write ()<br /> {<br /> <br /> char choice;<br /> cout << "do you want to input data to file ( y or n )" << endl;<br /> cin >> choice;<br /> cin.get(); //get newline<br /> while ( choice != 'y' &#038;& choice != 'n' )<br /> {<br /> cout << "bad choice!" << endl;<br /> cout << "do you want to input data to file ( y or n )" << endl;<br /> cin >> choice;<br /> cin.get(); //get newline<br /> }<br /> <br /> if ( choice == 'y' )<br /> {<br /> char inputText [ MAX_NAME ];<br /> cout << "enter input text: " << endl;<br /> cin.getline ( inputText , MAX_NAME , 'n' );<br /> <br /> ofstream outputFile;<br /> //PUT YOUR DATA FILE NAME HERE!<br /> outputFile.open ( "msngr.txt" , ios::app );<br /> outputFile << inputText << endl;<br /> outputFile.close();<br /> read();<br /> write();<br /> }<br /> <br /> }<br /> main(){<br /> cout << "Enter your username: ";<br /> cin >> username;<br /> read();<br /> write();<br /> <br /> <br /> return (0);<br /> }<br /> <br /> </fstream></iostream>

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73

<br /> #include <iostream><br /> #include <fstream><br /> #include <string.h><br /> #include <stdlib.h><br /> #define MAX_NAME 1000<br /> <br /> <br /> using namespace std;<br /> char sendtext;<br /> char username;<br /> <br /> void read(){<br /> system("cls");<br /> cout << "You autorised as:" << username << "n";<br /> ifstream in;<br /> in.open("msngr.txt");<br /> if (!in) {<br /> cout << "Input file cannot be opened.n";<br /> //return(1);<br /> }<br /> char str[20000];<br /> while (!in.eof()) {<br /> in >> str;<br /> cout << str << "n";<br /> strcpy(str, "");<br /> }<br /> cout << "n";<br /> in.close();<br /> <br /> }<br /> void write ()<br /> {<br /> <br /> char choice;<br /> cout << "do you want to input data to file ( y or n )" << endl;<br /> cin >> choice;<br /> cin.get(); //get newline<br /> while ( choice != 'y' &#038;& choice != 'n' )<br /> {<br /> cout << "bad choice!" << endl;<br /> cout << "do you want to input data to file ( y or n )" << endl;<br /> cin >> choice;<br /> cin.get(); //get newline<br /> }<br /> <br /> if ( choice == 'y' )<br /> {<br /> char inputText [ MAX_NAME ];<br /> cout << "enter input text: " << endl;<br /> cin.getline ( inputText , MAX_NAME , 'n' );<br /> <br /> ofstream outputFile;<br /> //PUT YOUR DATA FILE NAME HERE!<br /> outputFile.open ( "msngr.txt" , ios::app );<br /> outputFile << inputText << endl;<br /> outputFile.close();<br /> read();<br /> write();<br /> }<br /> <br /> }<br /> main(){<br /> cout << "Enter your username: ";<br /> cin >> username;<br /> read();<br /> write();<br /> <br /> <br /> return (0);<br /> }<br /> <br /> </fstream></iostream>

but there is some problems too.
when i enter username it writes only first the letter of the username and all other letters understands as answer to the confirmation and writes

You autorised as:N
do you want to input data to file ( y or n )
bad choice!
do you want to input data to file ( y or n )
bad choice!
do you want to input data to file ( y or n )

and when it shows the data of the file it puts n after all words and when i write “something is wrong”
it shows
something
is
wrong
but in file everything is ok

[GWILouisaxwzkla]

This seems to work:

<br /> <br /> #include <iostream><br /> #include <fstream><br /> #include <string.h><br /> #include <stdlib.h><br /> #include <ctype.h><br /> #define MAX_NAME 1000<br /> <br /> <br /> using namespace std;<br /> char sendtext;<br /> char username [ MAX_NAME ];<br /> <br /> void read(){<br /> system("cls");<br /> cout << "You autorised as:" << username << "n";<br /> ifstream in;<br /> in.open("c:\programs\in1.txt");<br /> if (!in) {<br /> cout << "Input file cannot be opened.n";<br /> //return 1;<br /> }<br /> char str[20000];<br /> while (!in.eof()) {<br /> in >> str;<br /> cout << str << "n";<br /> <br /> }<br /> cout << "n";<br /> in.close();<br /> <br /> }<br /> void write ()<br /> {<br /> char badInput;<br /> char choice;<br /> cout << "do you want to input data to file ( y or n )" << endl;<br /> cin >> choice;<br /> cin.get(); //get newline<br /> while ( tolower ( choice ) != 'y' &#038;& tolower ( choice ) != 'n' )<br /> {<br /> badInput = cin.get();<br /> while ( badInput != 'n' ) //clear garbage out of stream<br /> {<br /> badInput = cin.get();<br /> }<br /> cout << "bad choice!" << endl;<br /> cout << "do you want to input data to file ( y or n )" << endl;<br /> cin >> choice;<br /> cin.get(); //get newline<br /> }<br /> <br /> if ( tolower ( choice ) == 'y' )<br /> {<br /> char inputText [ MAX_NAME ];<br /> cout << "enter input text: " << endl;<br /> cin.getline ( inputText , MAX_NAME , 'n' );<br /> <br /> ofstream outputFile;<br /> //PUT YOUR DATA FILE NAME HERE!<br /> outputFile.open ( "msngr.txt" , ios::app );<br /> outputFile << inputText << endl;<br /> outputFile.close();<br /> read();<br /> write();<br /> }<br /> <br /> }<br /> main(){<br /> cout << "Enter your username: ";<br /> cin >> username;<br /> cin.get();<br /> read();<br /> write();<br /> <br /> <br /> return (0);<br /> }<br /> </fstream></iostream>

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80

<br /> <br /> #include <iostream><br /> #include <fstream><br /> #include <string.h><br /> #include <stdlib.h><br /> #include <ctype.h><br /> #define MAX_NAME 1000<br /> <br /> <br /> using namespace std;<br /> char sendtext;<br /> char username [ MAX_NAME ];<br /> <br /> void read(){<br /> system("cls");<br /> cout << "You autorised as:" << username << "n";<br /> ifstream in;<br /> in.open("c:\programs\in1.txt");<br /> if (!in) {<br /> cout << "Input file cannot be opened.n";<br /> //return 1;<br /> }<br /> char str[20000];<br /> while (!in.eof()) {<br /> in >> str;<br /> cout << str << "n";<br /> <br /> }<br /> cout << "n";<br /> in.close();<br /> <br /> }<br /> void write ()<br /> {<br /> char badInput;<br /> char choice;<br /> cout << "do you want to input data to file ( y or n )" << endl;<br /> cin >> choice;<br /> cin.get(); //get newline<br /> while ( tolower (  choice ) != 'y' &#038;&  tolower ( choice ) != 'n' )<br /> {<br /> badInput = cin.get();<br /> while ( badInput != 'n' ) //clear garbage out of stream<br /> {<br /> badInput = cin.get();<br /> }<br /> cout << "bad choice!" << endl;<br /> cout << "do you want to input data to file ( y or n )" << endl;<br /> cin >> choice;<br /> cin.get(); //get newline<br /> }<br /> <br /> if ( tolower ( choice  ) == 'y' )<br /> {<br /> char inputText [ MAX_NAME ];<br /> cout << "enter input text: " << endl;<br /> cin.getline ( inputText , MAX_NAME , 'n' );<br /> <br /> ofstream outputFile;<br /> //PUT YOUR DATA FILE NAME HERE!<br /> outputFile.open ( "msngr.txt" , ios::app );<br /> outputFile << inputText << endl;<br /> outputFile.close();<br /> read();<br /> write();<br /> }<br /> <br /> }<br /> main(){<br /> cout << "Enter your username: ";<br /> cin >> username;<br /> cin.get();<br /> read();<br /> write();<br /> <br /> <br /> return (0);<br /> }<br /> </fstream></iostream>

[050449]

Oh thanks it works well.

but can you explain what “cin.get()” means??
and what it used for?

and now i have to think how to remove confirmation

[050449]

ups problem. problem with read not solved it shows each word in new line

[GWILouisaxwzkla]

cin.get() is a member function that gets the next character from the input stream:

<br /> char ch;<br /> <br /> ch = cin.get(); //get a single character from the keyboard and store in 'ch'<br /> ch = cin.get(); //get a single character from the keyboard , but don't store it ( throw it out )<br /> <br />

1 2 3 4 5 6 7

<br /> char ch;<br /> <br /> ch = cin.get(); //get a single character from the keyboard and store in 'ch'<br /> ch = cin.get(); //get a single character from the keyboard , but don't store it ( throw it out )<br /> <br />

[050449]

thanks.and what about read() function ??

[GWILouisaxwzkla]

I think read() is for arrays. Check out this link on the topic: http://www.cplusplus.com/reference/iostream/istream/read.html

[050449]

Hi. I have a new problem now.

I am using C++ builder 2009 and i cannot make “tmaskedit” to show characters as “*” like in web

Can anyone help me?

[Author]

Posts