multiple line inputs in C - c

Question

I have to do the following things for my project
eg given an input such as
9 3 2 5
6 3 4 6 1
9 5 0 4 3 1
I will need to do the following things
i)divide the input in separate sets according to each line such as
set1={9,3,2,5)
set2={6,3,4,6,1}
set3={9,5,0,4,3,1}
ii)I will also need the individual elements in each set(such as 9,3,2,5 in set 1) as integers for further processing
notes:I am not allowed to give the input in a separate file so I tried entering as
"9 3 2 5\n6 3 4 6 1\n9 5 0 4 3 1"as pressing the enter after each line won't do as I will be required to give the full input in one go
Also I am required to use ONLY C
Any ideas to implement the above will be appreciated
Thank you for your help.

Answer 1

You can use fgets() to read the lines, and then strtok() to parse each line, this is a sample program, i've used the first element of the integer array as the array count, so you don't need to store it in a separate variable, I did that because I assume you can have different length arrays.
int freeArray(int **array, int setCount)
{
if (array == NULL)
return 0;
while (setCount > 0)
free(array[--setCount]);
free(array);
return -1;
}
void printArray(int *const *const array, int setCount)
{
int i;
for (i = 0 ; i < setCount ; ++i)
{
const int *pointer;
int j;
pointer = array[i];
if (pointer == NULL)
continue;
for (j = 1 ; j <= pointer[0] ; j++)
printf("%d ", pointer[j]);
printf("\n");
}
}
int *parseLine(char *line, int setCount)
{
char *pointer;
int count;
char *token;
int *array;
while ((*line != '\0') && (isspace(*line) != 0))
line++;
if (*line == '\0')
return NULL;
array = NULL;
pointer = line;
count = 0;
while ((token = strtok(pointer, " ")) != NULL)
{
char *endptr;
void *tmp;
pointer = NULL;
tmp = realloc(array, (1 + ++count) * sizeof(int));
if (tmp == NULL)
{
free(array);
return NULL;
}
array = tmp;
array[0] = count;
array[count] = strtol(token, &endptr, 10);
if ((*endptr != '\0') && ((*endptr != '\n')))
fprintf(stderr, "error: the %dth %s: value of the %dth line, is not an integer\n",
count, token, setCount);
}
return array;
}
int main(int argc, char **argv)
{
char line[256];
int **array;
int setCount;
line[0] = '\0';
array = NULL;
setCount = 0;
while (line[0] != '\n')
{
void *tmp;
if (fgets(line, sizeof(line), stdin) == NULL)
return -1;
tmp = realloc(array, (1 + setCount) * sizeof(int *));
if (tmp == NULL)
return freeArray(array, setCount);
array = tmp;
array[setCount] = parseLine(line, setCount);
if (array[setCount] != NULL)
setCount += 1;
}
printArray(array, setCount);
freeArray(array, setCount);
return 0;
}
at the end I show you how to access the elements of the array of arrays by printing them, and also how to free the malloced memory.
This program will exit when you press enter, but if you type a space before pressing enter, there will be problems, I'll let you think about a solution to that.