file io - C ,fscanf(), last line is read twice

Hi I’m doing a test program in C File I/O for my System
software (assemblers,loader etc ) course , my problem is the last line is read twice , I
remember my teacher told me this is due to some slight syntax or bug I missed ,I forgot
what it is , please take a look and help me
quick.

Program

#include
#include
//read
            from source.txt and write to output.txt

int
            main()
{
FILE *f1=fopen("source.txt","r");
FILE
            *f2=fopen("output.txt","w");
int address;
char
            label[20],opcode[20];

while(!feof(f1))//feof returns 1 if end of
            file
{
fscanf(f1,"%s\t%s\t%d",label,opcode,&address);
printf("%s\t%s\t%d\n",label,opcode,address);
fprintf(f2,"%s\t%s\t%d\n",label,opcode,address);
}
int
            check=fclose(f1);
int check2=fclose(f2);
printf("close status %d
            %d",check,check2);
return
            0;

}

source.txt

NULL
            LDA 4000
ALPHA STA 5000
BETA ADD 4020// I stopped right here, DID
            NOT PRESS 'ENTER' , so that ain’t the
            issue

output.txt

NULL
            LDA 4000
ALPHA STA 5000
BETA ADD 4020
BETA ADD
            4020

//last line
twice

output in
terminal

NULL LDA
            4000
ALPHA STA 5000
BETA ADD 4020
BETA ADD
            4020

//last line
twice

I don't want the last line to
be printed or written twice , what am I doing wrong , help!