Question

How to initialize 2D array with a list of values from text file using #include in C

Answer 1

#include <stdio.h>

#define SIZE 3

int main(int argc, char **argv)
{
    double array[SIZE][SIZE] = {
		#include "float_numbers.txt"
	};
	for (int i = 0; i < SIZE; i++) {
		for (int j = 0; j < SIZE; j++)
			printf("%9.3f", array[i][j]);
		printf("\n");
	}

    return 0;
}


/*
float_numbers.txt
-----------------
{3.14, 2.34, 5.238},
{98.23, 17.22, 5.51},
{93.4, 11.5, 88.33}

*/


/*
run:

    3.140    2.340    5.238
   98.230   17.220    5.510
   93.400   11.500   88.330

*/

 

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Answer 2

#include <stdio.h>

#define ROWS 3
#define COLS 2

int main(int argc, char **argv)
{
    double array[ROWS][COLS] = {
		#include "float_numbers.txt"
	};
	for (int i = 0; i < ROWS; i++) {
		for (int j = 0; j < COLS; j++)
			printf("%9.2f", array[i][j]);
		printf("\n");
	}

    return 0;
}

/*
float_numbers.txt
-----------------
{3.14, 2.348},
{98.23, 17.22},
{93.4, 11.5}

*/

/*
run:

     3.14     2.34
    98.23    17.22
    93.40    11.50

*/

 

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