The last line was printed twice

The last line is printed twice ( post #3)

I ran the new code but the last line is printed twice.

===========================
root:~# ./getdata3

# Samba SMB password file
public:501:85DBEE24101CEFF8AAD3B435B51404EEB51013B2730E1F16DF6DB7C3A73AD60:[U ]:LCT-3AB622A2:
user_name[] = public
admin:501:2B251B4003C6F043CA53DE06F7962527:C2D7C320A09B649A91AEC96D4CC32662:[UX ]:LCT-3E21AEC3:
user_name[] = admin

The last line below was printed twice

admin:501:2B251B4003C6F043CA53DE06F7962527:C2D7C320A09B649A91AEC96D4CC32662:[UX ]:LCT-3E21AEC3:
user_name[] = admin


===========================


int main(void)
{
FILE *in;
char buffer[255];
char user_name[32];
int n;
int i = 0;

if((in = fopen("/etc/samba/smbpasswd","r")) == NULL)
{
perror("Couldn't open file");
return 1;
}

while(!feof(in))

{
fgets(buffer, 255, in);
n = strlen(buffer) - 1;

if(n == 0)
printf("nothing read from file\n");
else
{
if(buffer[n] == '\n')
buffer[n] = '\0';
printf("%s\n", buffer);
}


for (i = 0; i <= 254; i++)
if (buffer[i] != ':')
user_name [i] = buffer[i];
else
{
user_name [i] = '\0';
printf ("user_name[] = %s\n", user_name);
break;
}
}

fclose(in);
return 0;
}

Handling end-of-file can always be a bit tricky. Basically, when you read zero bytes, then you've hit the end of the file. And until you make that failed attempt, the EOF status hasn't been set.

So you hit the end of the file, but you went on to output the "new line of data", which was just the old line unchanged. That's why the last line appears twice.

When you read zero bytes, either exit out of the loop (eg, with a break) or find some way to only print something out if you read new data.

If I test for zero byte, then how would the above code to be stested ?

while (!(eof) or file_pointer == "")

I would tend towards something like this:

The idea is that you only process the input data if the read was successful.

BTW, another way to test for fgets failing (including for an EOF condition) would be if it returns a NULL.

I did as you have suggested, but it still print the last line twice.

root:~# ./getdata4
# Samba SMB password file
public:501:85DBEE24101CEFF8AAD3B435B51404EEB51013B2730E1F16DF6DB7C3A73AD60:[U ]:LCT-3AB622A2:
j = 0
user_name[] = public

admin:501:2B251B4003C6F043CA53DE06F7962527:C2D7C320A09B649A91AEC96D4CC32662:[UX ]:LCT-3E21AEC3:
j = 1
user_name[] = admin

linh:1016:2B251B4003C6F043661B0422047CD33E:204093D0472B84F9671E87EDDF78B872:[UX ]:LCT-3F07F8F9:
j = 2
user_name[] = linh

------------ The last line is printed twice ------------------

linh:1016:2B251B4003C6F043661B0422047CD33E:204093D0472B84F9671E87EDDF78B872:[UX ]:LCT-3F07F8F9:
j = 3
user_name[] = linh

======================================

Try adding the following line as the first line of your do loop.

buffer[0] = '\0';

I suspect that fgets doesn't change the buffer if it doesn't read anything in. That means that the string from the last read is still there and you will print it out.

Thank you dwise1_aol and 3dfxMM for answering my questions.