How can I manipulate a data in a file for example the saved file is like this:
code name Price Quantity
001 hammer 100 4
002 screwdriver 100 4
what i like to do is:
1. the user will be ask to enter its code
2. will output the searched code and then
3. the user will be ask to enter how many pcs
he/she will buy.
the formula should be
pcs=pcs-users_input
if the user selected the code 001 and enters only 1pc it should be updated to only 3 pcs left in the file.
So where's your code attempt?
You should know by now that you can't just dump your assignment and expect code.
If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
If at first you don't succeed, try writing your phone number on the exam paper.
i don't know how to do it... that's why i'm asking...
just an example or link will do Mr. Thanks.
i do have a code here but i don't understand how it works....
something like this...Code:fp=fopen("prod.txt","r+"); while(!feof(fp)) { fgets(record,80,fp); drugs=strtok(record,";"); strcpy(num[x],drugs); drugs=strtok(NULL,";"); strcpy(name[x],drugs); drugs=strtok(NULL,";"); strcpy(gen[x],drugs); drugs=strtok(NULL,";"); strcpy(clas[x],drugs); drugs=strtok(NULL,";"); strcpy(manuf[x],drugs); drugs=strtok(NULL,";"); strcpy(price[x],drugs); drugs=strtok(NULL,""); x++; }
Some pointers to get you going
FAQ > Why it's bad to use feof() to control a loop - Cprogramming.com (There is also good sample code here)
There is a good sample of strtok at the end of this msdn page:
strtok, wcstok, _mbstok
Fact - Beethoven wrote his first symphony in C
Originally Posted by Click_here
What is the use of the putchar() and fgetc()
> i do have a code here but i don't understand how it works....
Well it would be better if you tried to write your own code - you know, one which parses 4 fields separated by spaces, as opposed to 7 fields separated by semicolons.
Seriously, read this
A development process
And if you get stuck, don't be afraid to create a separate project to test specific ideas.
Not sure how strtok() works, then write a 5-line program to test it!
Read the manual page, play around with the function - make sure you know how it works!Code:int main ( ) { char line[] = "this is a line\n"; // this is what fgets() would store char *token = strtok(line," "); printf("Line=%s, token=%s\n", line, token); token = strtok(line,NULL); // NULL means carry on from last time printf("Line=%s, token=%s\n", line, token); }
Don't just go round googling for code fragments, pasting bits of what you find on another forum, then asking people to basically rewrite it to match your assignment.
If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
If at first you don't succeed, try writing your phone number on the exam paper.
