Thread: rewrite to file

i want that my prog will rewrite (update) to exsist file if it was found a string im searching for inside this file, so i did this:

Code:

fptr=fopen("data.txt","r+"); // i also tried "a+"
fscanf(fptr,"%s\n",tmp_name); //tmp_name is a vector.
if (strcmp(myname,tmp_name)==0)
{
fprintf("%d %d %f %d",won,lost,avg,best);
}
fclose(fptr);

my file is a txt file and looks like this:

name1
1 2 3.3 5
name2
1 2 3.3 5

and i want to chk if name1==myname then change the 1 2 3.3 5 to 7 8 9.9 5
did what i was doing is illigel ? coz i cant get it to work...(the fprintf is doing nothing..), or maybe some1 know other way to do this ?
thanks !