structure to file [REMAIN UNSOLVED] [CLOSED]
-
#include <windows.h>
#include <conio.h>
#include <iostream>using namespace std;
struct Detail{
wchar_t Name[25];
long Age;
wchar_t Address[100];
};struct Student{
Detail detail;
DWORD code;
};int main()
{DWORD BytesWritten=0, BytesRead=0; Student st,read; st.code =1; st.detail.Name = TEXT("Williams"); st.detail.Age = 25; st.detail.Address = TEXT("B-33 Lane 5"); HANDLE hFile = CreateFile(TEXT("C:\\\\demo.txt"),GENERIC\_READ | GENERIC\_WRITE,0,0,OPEN\_ALWAYS,FILE\_ATTRIBUTE\_NORMAL,0); if (hFile != INVALID\_HANDLE\_VALUE) { WriteFile(hFile,&st,sizeof(Student),&BytesWritten,0); ReadFile(hFile,&read,sizeof(Student),&BytesRead,0); CloseHandle(hFile); cout<<read.code<<endl; cout<<read.detail.Name; } else { cout<<"Error! Cannot Open File"; exit(1); } \_getche(); return (0);}
when executing this code following error occurs.
Error 1 error C2440: '=' : cannot convert from 'const wchar_t [9]' to 'wchar_t [25]'
Error 2 error C2440: '=' : cannot convert from 'const wchar_t [12]' to 'wchar_t [100]'Some Day I Will Prove MySelf :: GOLD
st.detail.Name = TEXT("Williams");
You cannot copy characters in this way, you must use one of the copy methods.
I must get a clever new signature for 2011.
-
Try ZeroMemory
Student st,read;
ZeroMemory(&st,sizeof(st));I believe in LOVE AT FIRST SIGHT... Bcoz I have loved my Mother... even since I opened my eyes...(ICAN)
-
DavidCrow wrote:
You probably meant to use _tcscpy() here instead.
This works like a charm
_tcscpy(st.detail.Name,TEXT("Williams"));
_tcscpy(st.detail.Address,TEXT("B-33 Lane 5"));But another problem arises cannot set values in long and DWORD variables
struct Detail{
wchar_t Name[25];
long Age;
wchar_t Address[100];
};struct Student{
Detail detail;
DWORD code;
};Student st;
st.code = 1;but st.code stores a default value of -16843010 and same problem with long data type st.Details.Age = 25 stores 65278, instead of 25.:confused: :wtf: MODIFIED: _tcscpy_s() now works. i was making a small mistake. Now it works.._tcscpy_s(st.detail.Name,_tcslen(st.detail.Name),TEXT("WILLIAMS"));
Some Day I Will Prove MySelf :: GOLD
modified on Wednesday, February 16, 2011 10:43 PM
goldenrose9 wrote:
i was making a small mistake.
And you still are.
_tcslen()does not tell you the size/capacity ofName, but rather how many characters it is currently holding."One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"Man who follows car will be exhausted." - Confucius
-
goldenrose9 wrote:
i was making a small mistake.
And you still are.
_tcslen()does not tell you the size/capacity ofName, but rather how many characters it is currently holding."One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"Man who follows car will be exhausted." - Confucius
yes you are right. but when i use
_tcscpy_s(st.detail.Name,sizeof(st.detail.Name),TEXT("WILLIAMS"));
stack around
stget corrupted. moreover when i initialize st withst.code =1;
st.detail.Age = 25;then the value is changed to
st.code = 4278124286
st.detail.Age = -16843010i had intialized the st as given
st.code =1;
st.detail.Age = 25;
_tcscpy_s(st.detail.Name,sizeof(st.detail.Name),TEXT("WILLIAMS"));
_tcscpy_s(st.detail.Address,sizeof(st.detail.Address),TEXT("BB-33 LANE 5"));Some Day I Will Prove MySelf :: GOLD
-
yes you are right. but when i use
_tcscpy_s(st.detail.Name,sizeof(st.detail.Name),TEXT("WILLIAMS"));
stack around
stget corrupted. moreover when i initialize st withst.code =1;
st.detail.Age = 25;then the value is changed to
st.code = 4278124286
st.detail.Age = -16843010i had intialized the st as given
st.code =1;
st.detail.Age = 25;
_tcscpy_s(st.detail.Name,sizeof(st.detail.Name),TEXT("WILLIAMS"));
_tcscpy_s(st.detail.Address,sizeof(st.detail.Address),TEXT("BB-33 LANE 5"));Some Day I Will Prove MySelf :: GOLD
Have you considered:
st.code = 1;
st.st.Age = 25;
_tcscpy_s(st.st.Name, sizeof(st.st.Name), TEXT("WILLIAMS"));
_tcscpy_s(st.st.Address, sizeof(st.st.Address), TEXT("BB-33 LANE 5"));For clarities sake, you might consider renaming the
stmember ofStudent."One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"Man who follows car will be exhausted." - Confucius
-
Have you considered:
st.code = 1;
st.st.Age = 25;
_tcscpy_s(st.st.Name, sizeof(st.st.Name), TEXT("WILLIAMS"));
_tcscpy_s(st.st.Address, sizeof(st.st.Address), TEXT("BB-33 LANE 5"));For clarities sake, you might consider renaming the
stmember ofStudent."One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"Man who follows car will be exhausted." - Confucius
whenever
st.codeandst.st.Ageis initialized with any value the result is,st.code = 4278124286
st.detail.Age = -16843010Some Day I Will Prove MySelf :: GOLD
-
whenever
st.codeandst.st.Ageis initialized with any value the result is,st.code = 4278124286
st.detail.Age = -16843010Some Day I Will Prove MySelf :: GOLD
You need to look more closely at the code snippet I provided. You should not be assigning or referencing
st.Detail. In yourStudentstructure,Detailis a type of structure, not an instance of one."One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"Man who follows car will be exhausted." - Confucius
-
You need to look more closely at the code snippet I provided. You should not be assigning or referencing
st.Detail. In yourStudentstructure,Detailis a type of structure, not an instance of one."One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"Man who follows car will be exhausted." - Confucius
please give a small example. :confused:
Some Day I Will Prove MySelf :: GOLD
-
please give a small example. :confused:
Some Day I Will Prove MySelf :: GOLD
See here.
"One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"Man who follows car will be exhausted." - Confucius
-
See here.
"One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"Man who follows car will be exhausted." - Confucius
on using
st.code = 1;
st.st.Age = 25;
_tcscpy_s(st.st.Name, sizeof(st.st.Name), TEXT("WILLIAMS"));
_tcscpy_s(st.st.Address, sizeof(st.st.Address), TEXT("BB-33 LANE 5"));following error occurs.
Error 1 error C2039: 'st' : is not a member of 'Student'
Error 2 error C2228: left of '.Age' must have class/struct/unionSome Day I Will Prove MySelf :: GOLD
-
on using
st.code = 1;
st.st.Age = 25;
_tcscpy_s(st.st.Name, sizeof(st.st.Name), TEXT("WILLIAMS"));
_tcscpy_s(st.st.Address, sizeof(st.st.Address), TEXT("BB-33 LANE 5"));following error occurs.
Error 1 error C2039: 'st' : is not a member of 'Student'
Error 2 error C2228: left of '.Age' must have class/struct/unionSome Day I Will Prove MySelf :: GOLD
I just compiled your code with my changes. It compiled and ran fine.
"One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"Man who follows car will be exhausted." - Confucius
-
I just compiled your code with my changes. It compiled and ran fine.
"One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"Man who follows car will be exhausted." - Confucius
please give a sample so that i can understand my mistake.
Some Day I Will Prove MySelf :: GOLD