97 lines
2.3 KiB
C
97 lines
2.3 KiB
C
/* License: AGPLv3 or later. https://www.gnu.org/licenses/licenses.html
|
|
*
|
|
* Exercise 3 - Virtual Initialization (Week 4)
|
|
* Name: Manish
|
|
* Student Login: *****
|
|
*
|
|
* Compile as:
|
|
* $ gcc -std=c11 -Wall -o ex3 ex3.c
|
|
*
|
|
* Assumption: Where input is 0 indexed and not starting from 1
|
|
*/
|
|
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
|
|
int data[100];
|
|
int forward[100];
|
|
int backward[100];
|
|
int valid_indexes = -1;
|
|
|
|
|
|
int main(void)
|
|
{
|
|
printf("Enter file name: ");
|
|
char filename[257];
|
|
// Assuming filename/file path won't be longer than 256 characters
|
|
scanf("%256s", filename);
|
|
|
|
FILE* file = fopen(filename, "r");
|
|
if (!file)
|
|
{
|
|
perror(filename);
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
|
|
int what = -10;
|
|
int where = -10;
|
|
// Trailing whitespaces to consume all subsequent ' ', \t, \n, \r
|
|
/* NOTE: Not using file position checks to detect when stuck in a loop
|
|
* assuming input to be in exact format as specified
|
|
*/
|
|
while (fscanf(file, " %d ", &what) != EOF
|
|
&& fscanf(file, " %d ", &where) !=EOF)
|
|
{
|
|
if (what == -1 && where == -1)
|
|
{
|
|
break;
|
|
}
|
|
// Where/index cannot be less than 0
|
|
if (where < 0 || where >= 100)
|
|
{
|
|
fprintf(
|
|
stderr,
|
|
"Where index is %d but arrays index is only up to 99. "
|
|
"Ignoring this input.\n",
|
|
where);
|
|
continue;
|
|
}
|
|
data[where] = what;
|
|
forward[++valid_indexes] = where;
|
|
backward[where] = valid_indexes;
|
|
}
|
|
|
|
int probe;
|
|
// Trailing whitespace to consume all subsequent ' ', \t, \n, \r
|
|
while(fscanf(file, " %d ", &probe) != EOF)
|
|
{
|
|
if (probe == -1)
|
|
{
|
|
break;
|
|
}
|
|
// Probe/index cannot be less than 0
|
|
if (probe < 0 || probe >= 100)
|
|
{
|
|
printf("Position %d does not exist.\n",probe);
|
|
continue;
|
|
}
|
|
if (backward[probe] <= valid_indexes
|
|
&& forward[backward[probe]] == probe)
|
|
{
|
|
printf(
|
|
"Position %d has been initialized to value %d.\n",
|
|
probe,
|
|
data[probe]
|
|
);
|
|
}
|
|
else
|
|
{
|
|
printf("Position %d has not been initialized.\n", probe);
|
|
}
|
|
}
|
|
|
|
fclose(file);
|
|
|
|
return 0;
|
|
}
|