clearing the data in a file

[mickey22]

I have a file already written and I want to clear all the contents in it.

code:

int number=10;
FILE *fp;
fopen_s(&fp,"a.txt","a");
/////want to clear the data here in a.txt file
fprintf(fp,"%d",number);
fclose(fp);

after opening the file I want to clear all the contents first and then print the number in the a.txt.I tried used the flushall function.It did not work or may be I may not have used properly.

Could anyone give me idea how to do this operation?
Thanks

[sicarie]

fopen_s(&fp,"a.txt","a");

You're opening the file in append mode by specifying the 'a' right behind the filename. Use a 'w' for 'write' and you will wipe out the contents that are currently in the file.