Imtiaz Raqib Imtiaz Raqib - 26 days ago 9
C Question

Storing numbers as (x, y) cordinates from a file at a specific point

I have an Instance File from which I need to store the NUM_PT and all the respective co-ordinates in the form of a 2D array system (personal choice so I can access them easily). I am able to retrieve the NUM_PT but I am stuck at reading the successive cordinates into my array.

HERE IS WHAT I HAVE DONE

/* Assignment 2 */

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <time.h>
#include <ctype.h>



#define MAXS 256

int main(int argc, char *argv[])

{

int num_pt;
int inputfile = 0, outputfile = 0, i;

for (i = 1; i < argc; i++)
{
if (strcmp (argv[i], "-i") == 0)
inputfile = i+1;
if (strcmp (argv[i], "-o") == 0)
outputfile = i+1;
}
if (inputfile == 0)
{
/* invalid command line options */
printf("\nIncorrect command-line...\n");
printf("> %s [-i inputfile [-o outputfile]]\n\n", argv[0]);
exit(0);
}

FILE *fp;
fp = fopen(argv[inputfile], "r");

int count = 0;
if (fp == 0)
{
printf("\nCould not find %s\n", argv[inputfile]);
exit(0);
}

char line[MAXS];
while (fgets(line, sizeof line, fp) != NULL)
{
if (count == 4)
{
fscanf(fp, "%d", &num_pt);
break;
}
else
count++;

}

int arr[num_pt][1];
while (fgets(line, sizeof line, fp) != NULL)
{
if (count == 5)
{
int k, j, cord;
for (k = 0; k < num_pt; k++)
{
for (j = 0; j < num_pt; j++)
{
while (fscanf(fp, "%d%d", &cord) > 0)
{
arr[k][j] = cord;
j++;
}
}
}
}
}
fclose(fp)
return 0;

}


After retrieving NUM_PT i tried reinitializing the
count
to 5 because the cordinates start from **LINE 6* in the file.

ERROR FROM COMPILERubuntu bash script

Language: c99 ; Compiler: gcc

Answer

sample for "Storing numbers as (x, y) cordinates from a file" (It is better not to fix the reading position)

#include <stdio.h>

typedef struct point {
    int x, y;
} Point;

int readPoint(FILE *fp, Point *p);
int readInt(FILE *fp, int *n);

int main(void){
    FILE *fp = fopen("instance10_001.txt", "r");
    Point p;
    int MAX_X, MAX_Y;

    readPoint(fp, &p);
    MAX_X = p.x;
    MAX_Y = p.y;
    printf("MAX_X:%d, MAX_Y:%d\n", MAX_X, MAX_Y);

    int NUM_PT;
    readInt(fp, &NUM_PT);
    printf("NUM_PT:%d\n", NUM_PT);

    Point arr[NUM_PT];
    for(int i = 0; i < NUM_PT; ++i){
        readPoint(fp, &arr[i]);
        printf("Point(%d, %d)\n", arr[i].x, arr[i].y);
    }
    fclose(fp);
}

int readLine(FILE *fp, char *buff, int buff_size){
    while(fgets(buff, buff_size, fp)){
        if(*buff == '#' || *buff == '\n')
            continue;
        return 1;
    }
    return 0;
}

#define LINE_MAX 128
int readPoint(FILE *fp, Point *p){
    char buff[LINE_MAX];
    if(readLine(fp, buff, sizeof buff)){
        return 2 == sscanf(buff, "%d %d", &p->x, &p->y);
    }
    return 0;
}
int readInt(FILE *fp, int *n){
    char buff[LINE_MAX];
    if(readLine(fp, buff, sizeof buff)){
        return 1 == sscanf(buff, "%d", n);
    }
    return 0;
}