2D array - I want to find which collums have 1s in them in each row
My input looks like this :
15 5
0 0 1 0 0
0 0 1 0 0
0 0 1 0 0
0 0 0 0 0
0 0 0 0 0
1 0 0 0 0
0 1 0 1 0
0 0 1 0 0
0 0 0 0 1
0 0 0 0 0
0 0 0 0 0
0 1 0 0 0
1 0 0 0 1
0 0 1 0 0
0 0 0 1 0
The first row contains the number of rows and collums of my array. And basically i want to find out where these 1s are in the array.
So in the first 3 rows i want to get 3
, in the 7th 1
, and in the 8th, i want to get 2 3
etc..
My code looks like this so far
#include <stdio.h>
int main()
int row, collumn;
FILE* input;
FILE* output;
input = fopen("input.txt", "r");
if (input == 0)
printf("ERROR couldn't open input.txt");
return 1;
if (! fscanf(input, "%d %d", &row, &collumn))
printf("ERROR not recognised value");
fclose(input);
return 2;
output = fopen("output.txt", "w");
int meteor[row][collumn];
for (int i = 0; i < row; i++)
for (int j = 0; j < collumn; j++)
fscanf(input, "%d", &meteor[i][j]);
int sum;
int loc[row];
for (int i = 0; i < row; i++)
sum = 0;
for (int j = 0; j < collumn; j++)
sum += meteor[i][j];
if (meteor[i][j] == 1)
loc[i] = (j + 1);
printf("%d %dn", loc[i], sum);
fclose(input);
fclose(output);
return 0;
My output is this :
3 1
3 1
3 1
0 0
-1 0
1 1
4 2
3 1
5 1
0 0
4214921 0
2 1
5 2
3 1
4 1
The first collumn shows some of the locations, the second shows how many 1s are in the row, but it all fails when there are only 0s
in the row or there is more than one 1
. And also i would like to store these values.
c arrays
add a comment |
My input looks like this :
15 5
0 0 1 0 0
0 0 1 0 0
0 0 1 0 0
0 0 0 0 0
0 0 0 0 0
1 0 0 0 0
0 1 0 1 0
0 0 1 0 0
0 0 0 0 1
0 0 0 0 0
0 0 0 0 0
0 1 0 0 0
1 0 0 0 1
0 0 1 0 0
0 0 0 1 0
The first row contains the number of rows and collums of my array. And basically i want to find out where these 1s are in the array.
So in the first 3 rows i want to get 3
, in the 7th 1
, and in the 8th, i want to get 2 3
etc..
My code looks like this so far
#include <stdio.h>
int main()
int row, collumn;
FILE* input;
FILE* output;
input = fopen("input.txt", "r");
if (input == 0)
printf("ERROR couldn't open input.txt");
return 1;
if (! fscanf(input, "%d %d", &row, &collumn))
printf("ERROR not recognised value");
fclose(input);
return 2;
output = fopen("output.txt", "w");
int meteor[row][collumn];
for (int i = 0; i < row; i++)
for (int j = 0; j < collumn; j++)
fscanf(input, "%d", &meteor[i][j]);
int sum;
int loc[row];
for (int i = 0; i < row; i++)
sum = 0;
for (int j = 0; j < collumn; j++)
sum += meteor[i][j];
if (meteor[i][j] == 1)
loc[i] = (j + 1);
printf("%d %dn", loc[i], sum);
fclose(input);
fclose(output);
return 0;
My output is this :
3 1
3 1
3 1
0 0
-1 0
1 1
4 2
3 1
5 1
0 0
4214921 0
2 1
5 2
3 1
4 1
The first collumn shows some of the locations, the second shows how many 1s are in the row, but it all fails when there are only 0s
in the row or there is more than one 1
. And also i would like to store these values.
c arrays
1
if (! fscanf("%d %d .. )"
is invalid, this fscanf returns 2 on success and not 2 (EOF, 0 or 1) on failure.
– Kamil Cuk
Nov 12 '18 at 21:24
1
You never initializeloc
.
– Johnny Mopp
Nov 12 '18 at 21:24
add a comment |
My input looks like this :
15 5
0 0 1 0 0
0 0 1 0 0
0 0 1 0 0
0 0 0 0 0
0 0 0 0 0
1 0 0 0 0
0 1 0 1 0
0 0 1 0 0
0 0 0 0 1
0 0 0 0 0
0 0 0 0 0
0 1 0 0 0
1 0 0 0 1
0 0 1 0 0
0 0 0 1 0
The first row contains the number of rows and collums of my array. And basically i want to find out where these 1s are in the array.
So in the first 3 rows i want to get 3
, in the 7th 1
, and in the 8th, i want to get 2 3
etc..
My code looks like this so far
#include <stdio.h>
int main()
int row, collumn;
FILE* input;
FILE* output;
input = fopen("input.txt", "r");
if (input == 0)
printf("ERROR couldn't open input.txt");
return 1;
if (! fscanf(input, "%d %d", &row, &collumn))
printf("ERROR not recognised value");
fclose(input);
return 2;
output = fopen("output.txt", "w");
int meteor[row][collumn];
for (int i = 0; i < row; i++)
for (int j = 0; j < collumn; j++)
fscanf(input, "%d", &meteor[i][j]);
int sum;
int loc[row];
for (int i = 0; i < row; i++)
sum = 0;
for (int j = 0; j < collumn; j++)
sum += meteor[i][j];
if (meteor[i][j] == 1)
loc[i] = (j + 1);
printf("%d %dn", loc[i], sum);
fclose(input);
fclose(output);
return 0;
My output is this :
3 1
3 1
3 1
0 0
-1 0
1 1
4 2
3 1
5 1
0 0
4214921 0
2 1
5 2
3 1
4 1
The first collumn shows some of the locations, the second shows how many 1s are in the row, but it all fails when there are only 0s
in the row or there is more than one 1
. And also i would like to store these values.
c arrays
My input looks like this :
15 5
0 0 1 0 0
0 0 1 0 0
0 0 1 0 0
0 0 0 0 0
0 0 0 0 0
1 0 0 0 0
0 1 0 1 0
0 0 1 0 0
0 0 0 0 1
0 0 0 0 0
0 0 0 0 0
0 1 0 0 0
1 0 0 0 1
0 0 1 0 0
0 0 0 1 0
The first row contains the number of rows and collums of my array. And basically i want to find out where these 1s are in the array.
So in the first 3 rows i want to get 3
, in the 7th 1
, and in the 8th, i want to get 2 3
etc..
My code looks like this so far
#include <stdio.h>
int main()
int row, collumn;
FILE* input;
FILE* output;
input = fopen("input.txt", "r");
if (input == 0)
printf("ERROR couldn't open input.txt");
return 1;
if (! fscanf(input, "%d %d", &row, &collumn))
printf("ERROR not recognised value");
fclose(input);
return 2;
output = fopen("output.txt", "w");
int meteor[row][collumn];
for (int i = 0; i < row; i++)
for (int j = 0; j < collumn; j++)
fscanf(input, "%d", &meteor[i][j]);
int sum;
int loc[row];
for (int i = 0; i < row; i++)
sum = 0;
for (int j = 0; j < collumn; j++)
sum += meteor[i][j];
if (meteor[i][j] == 1)
loc[i] = (j + 1);
printf("%d %dn", loc[i], sum);
fclose(input);
fclose(output);
return 0;
My output is this :
3 1
3 1
3 1
0 0
-1 0
1 1
4 2
3 1
5 1
0 0
4214921 0
2 1
5 2
3 1
4 1
The first collumn shows some of the locations, the second shows how many 1s are in the row, but it all fails when there are only 0s
in the row or there is more than one 1
. And also i would like to store these values.
c arrays
c arrays
asked Nov 12 '18 at 21:17
Stan MarshStan Marsh
216
216
1
if (! fscanf("%d %d .. )"
is invalid, this fscanf returns 2 on success and not 2 (EOF, 0 or 1) on failure.
– Kamil Cuk
Nov 12 '18 at 21:24
1
You never initializeloc
.
– Johnny Mopp
Nov 12 '18 at 21:24
add a comment |
1
if (! fscanf("%d %d .. )"
is invalid, this fscanf returns 2 on success and not 2 (EOF, 0 or 1) on failure.
– Kamil Cuk
Nov 12 '18 at 21:24
1
You never initializeloc
.
– Johnny Mopp
Nov 12 '18 at 21:24
1
1
if (! fscanf("%d %d .. )"
is invalid, this fscanf returns 2 on success and not 2 (EOF, 0 or 1) on failure.– Kamil Cuk
Nov 12 '18 at 21:24
if (! fscanf("%d %d .. )"
is invalid, this fscanf returns 2 on success and not 2 (EOF, 0 or 1) on failure.– Kamil Cuk
Nov 12 '18 at 21:24
1
1
You never initialize
loc
.– Johnny Mopp
Nov 12 '18 at 21:24
You never initialize
loc
.– Johnny Mopp
Nov 12 '18 at 21:24
add a comment |
1 Answer
1
active
oldest
votes
You need to initialize loc
.. If you look carefully at your code, you only populate it on the condition of if (meteor[i][j] == 1)
... but you print it for every index of i. which would print uninitialized memory (i.e. unknown).
To answer the second part of your question, if you want to store the "sum". Simply make loc
a 2d array just like meteor
, but with 2 columns (row and sum). i.e. int loc[row][2]
.. making sure to initialize both columns of course :)
add a comment |
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1 Answer
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active
oldest
votes
active
oldest
votes
active
oldest
votes
You need to initialize loc
.. If you look carefully at your code, you only populate it on the condition of if (meteor[i][j] == 1)
... but you print it for every index of i. which would print uninitialized memory (i.e. unknown).
To answer the second part of your question, if you want to store the "sum". Simply make loc
a 2d array just like meteor
, but with 2 columns (row and sum). i.e. int loc[row][2]
.. making sure to initialize both columns of course :)
add a comment |
You need to initialize loc
.. If you look carefully at your code, you only populate it on the condition of if (meteor[i][j] == 1)
... but you print it for every index of i. which would print uninitialized memory (i.e. unknown).
To answer the second part of your question, if you want to store the "sum". Simply make loc
a 2d array just like meteor
, but with 2 columns (row and sum). i.e. int loc[row][2]
.. making sure to initialize both columns of course :)
add a comment |
You need to initialize loc
.. If you look carefully at your code, you only populate it on the condition of if (meteor[i][j] == 1)
... but you print it for every index of i. which would print uninitialized memory (i.e. unknown).
To answer the second part of your question, if you want to store the "sum". Simply make loc
a 2d array just like meteor
, but with 2 columns (row and sum). i.e. int loc[row][2]
.. making sure to initialize both columns of course :)
You need to initialize loc
.. If you look carefully at your code, you only populate it on the condition of if (meteor[i][j] == 1)
... but you print it for every index of i. which would print uninitialized memory (i.e. unknown).
To answer the second part of your question, if you want to store the "sum". Simply make loc
a 2d array just like meteor
, but with 2 columns (row and sum). i.e. int loc[row][2]
.. making sure to initialize both columns of course :)
edited Nov 12 '18 at 21:36
answered Nov 12 '18 at 21:29
static_caststatic_cast
82211018
82211018
add a comment |
add a comment |
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1
if (! fscanf("%d %d .. )"
is invalid, this fscanf returns 2 on success and not 2 (EOF, 0 or 1) on failure.– Kamil Cuk
Nov 12 '18 at 21:24
1
You never initialize
loc
.– Johnny Mopp
Nov 12 '18 at 21:24