fgets doesn't move file pointer - c

Question

I have a question which maybe fairly simple. I have a file input.txt which is:
cat input.txt
testsuite1
test1
summary information of test
FAIL
testsuite2
test1
summary info ya
PASS
I am writing a program just to read each of these strings into variables and do further processing. What is the best way to do it? I am currently doing:
main() {
FILE *fp;
char testsuite[100],testname[100],summary[100],result[100];
fp = fopen("input.txt", "r");
while(1) {
if(fgets(testsuite,99,fp) == NULL)
{
ferror(fp);
break;
}
if(fgets(testname,99,fp) == NULL)
{
ferror(fp);
break;
}
if(fgets(summary,99,fp) == NULL)
{
ferror(fp);
break;
}
if(fgets(result,99,fp) == NULL)
{
ferror(fp);
break;
}
printf("testsuite: %s testname:%s summary:%s result:%s \n",testsuite,testname,summary,result);
}
fclose(fp);
}
Is there a better way to do it? The problem I am currently facing is that, if input.txt contains even one blank line, the blank like is read into a variable. Whats the best way to avoid it?
Thanks!

Answer 1

You should write your own function that skips empty lines (e.g. called getline()) and use it instead of fgets():
char *getline(char *buf, int size, FILE *fp)
{
char *result;
do {
result = fgets(buf, size, fp);
} while( result != NULL && buf[0] == '\n' );
return result;
}
You could now refine that function to also skip lines that consist of blanks only or whatever you need.

Answer 2

You can remove all blank lines of your files before your loop while.
After the open you parse the whole file and remove the blank ;).
But it don't seems like the best way to do it.
Overwise you can check after each fget if your variables are empty, and in this case, fget again.
Hope that will be helpfull.

Answer 3

If you do this, you will not be able to use the strings you read once loop quits, since each loop overwrites each string in the buffer. However, you could store your strings in a struct array:
typedef struct {
testsuite[100];
testname[100];
summary[100];
result[100];
}test;
test test_array[2];
int main(){
int iIndex=0;
FILE* fpPtr=NULL;
fpPtr = fopen("input.txt", "r");
if(fpPtr==NULL){ //<--- it is very important to check if fopen fails
perror("fopen");
}
for(iIndex=0; iIndex<2; iIndex++){ // 2 because it is the number of elements in test_array
if(fgets(test_array[i].testsuite,99,fp) == NULL)
{
ferror(fp);
break;
}
if(fgets(test_array[i].testname,99,fp) == NULL)
{
ferror(fp);
break;
}
if(fgets(test_array[i].summary,99,fp) == NULL)
{
ferror(fp);
break;
}
if(fgets(test_array[i].result,99,fp) == NULL)
{
ferror(fp);
break;
}
}
}
You can detect blank lines by checking for a newline character at position 0:
fgets(cBuffer, sizeof(cBuffer), fpPtr);
//<-- if the file was created on windows, check for '\r' instead, since a new line in windows is \r\n
if(cBuffer[0]=='\n')
{
printf("blank line"\n);
}