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