I\o

[ghadahelal]

hallo
i want 2 know if there is a function that reads from an input file and after reading this char will disapear.
i mean the read char will b disappeared.

hallo
i want 2 know if there is a function that reads from an input file and after reading this char will disapear.
i mean the read char will b disappeared.

If not you could just write your own.

[ghadahelal]

or can i read and write in the same file

[jetru]

Yes. You CAN read and wrte in the same file. You will have to use fstream to declare your stream.

http://www.daniweb.com/tutorials/tutorial6542.html

You will have to read the file into memory, change it there and then write it back if you want the read character to be deleted.

[ghadahelal]

how i can read the file in memory
i want the char 2 b saved in memory not a copy

[jetru]

You have to copy everything after your character into an array or something, then come back and overwrite the character. Did you get me?

[Ancient Dragon]

I think you need a clearer definition of what you want. characters don't just "disappear" -- unless your a magician.

Post an example of what you want. For example, if the word "hello" is read, do you want to delete the two 'l's and make it "heo"?

[ghadahelal]

for ex:
here is my input file ack=100 , and i want 2 read the four chars ack= and then after reading the input file will b as shown 100

for ex:
here is my input file ack=100 , and i want 2 read the four chars ack= and then after reading the input file will b as shown 100

I don't no what you mean? :sad:
What is ack?

[Narue]

>then after reading the input file will b as shown 100
Files are persistent, they don't work like that. If you want a destructive read, you'll need to build it yourself by rewriting the file. Since that's an expensive operation, you'll want to seriously consider whether you really need this feature or not.

[Ancient Dragon]

for ex:
here is my input file ack=100 , and i want 2 read the four chars ack= and then after reading the input file will b as shown 100

If I understand you, you want to put the value 100 into an integer variable:?: If that is true, you have a couple options:
(1) use sscanf(), or (2) pointer parsing. There are other options in c++ using stringstream class.

char buf[20];
int n;
// read a line into buf is not shown
//buf[] = "ack=100"; after read
//
sscanf(buf,"ack=%d",&n); // now n == 100

(2) parse with a pointer

char buf[20];
char* ptr;
int n;
// read a line into buf is not shown
//buf[] = "ack=100"; after read
//
ptr = strchr(buf,'='); // locate the '=' symbol
n = atoi(ptr+1); // convert remainder to int