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EndLau

Hello, I've got a C++ task that I need to do but I wasn't learning C++ before and it's kinda hard for me, so I decided to ask you guys for help. Here's the task: You have a two dimensional massive E[m][n]. m = 4, n = 3. All the negative massive elements need to be changed to the columns that the element is in sum. The answers need to be put in a .txt file.
Would there be a person who could help me with this? The only thing I know how to do is the second part where I need to write the answers in the .txt file.
A bump from time to time would be nice :)

9 years ago

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Is C++ hard?

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Yes, yes of course
Hell no.
Potato cannon nerf gun
33 Comments
Saotoshi

Bump for solved:) Thanks a lot!

9 years ago
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Tyler889

I think you need to learn a 2D array, or a multi-dimensional array. The structure is the same for the others languages, then your time is not wasted ;)

9 years ago
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PraiseRhllor

All the negative massive elements need to be changed to the columns that the element is in sum.

ehrm could you repeat this with other words :O

9 years ago
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EndLau

Hmm, If an element in the massive is negative, it needs to be change to the sum of the column that it is in. :D that's as best as I can do with the translating of it :D

9 years ago
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PraiseRhllor

basically 2 FOR, one for M and an inner FOR for N

9 years ago
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Tyler889

Manco io ci ho capito una mazza, ma fortunatamente per lui so di cosa ha bisogno ;P

9 years ago
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PraiseRhllor

ho intuito che fosse una matrice, ma non l'ho mai sentita chiamare massive onestamente xD

9 years ago
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Tyler889

... gli scherzi di google traduttore :D

9 years ago
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TheDopefish

the entitity of gloomy colossal particles demand transformation directed toward the cavalcada such piece befalls amount

there, I used a thesaurus on every word :D

https://www.youtube.com/watch?v=DW1lxwsK5_Q

9 years ago*
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atb85

10/10 I would Greenlight that.

9 years ago
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Tzaar

I ... ummm.

THE ANSWER IS GREEN!

(free bump?)

9 years ago
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PorkyPhill

ummm who gave you this C++ task?

9 years ago
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EndLau

It was Lord GabeN himself

9 years ago
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PorkyPhill

Lord GabeN could have done that faster than asking the question upon you thou ;)

9 years ago
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EndLau

Could he though, could he?

9 years ago
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darthHottabich

for (i = 0; i < 4; i++) { for (j = 0; j < 3; j++) { if (arr[i][j] < 0) { arr[i][j] = (i+1) + (j+1); } } }

I give up on this markup.

9 years ago
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ozo2003

why i+1 and j+1? if it's a sum of column, shouldn't it be i+i?

9 years ago
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darthHottabich

Indexes of array start from 0 as I remember, so column 1 will have 0 index. (haven't seen any C++ code for 2 years)

UPD: +I think EndLau need column and row sum, not colunm and column.

9 years ago*
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ozo2003

ok, if from that point of view. but it's still, sum of column, so should be i+i (+2), why go with j+1 too, than it would be sum of column + row. that might be what he's asking tho, translation might be off as well, who knows

9 years ago
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EndLau

It says to change all the negative elements to the sum of a column that the element is in.

9 years ago
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darthHottabich

Got it, not index (number), but values of column.)

9 years ago
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TheDopefish

replace arr[i][j] = (i+1) + (j+1);

with sth like

arr[i][j] = 0; for (n = 0; n < 3; n++) { arr[i][j] += arr[i][n] }

9 years ago
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Greffin28

Not a master of C++ but i think this should work.
Edit 2: nevermind my code, i didn't see it's only column :p

9 years ago*
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TheDopefish

not sure, maybe my english s bad or OP chose bad wording, but we don't even know which of this 2D array is the row and which the column.

you're suggesting to sum up all elements of the array, while I'm suggesting that the second array represents the column, and only add up the column, because:

All the negative massive elements need to be changed to the columns that the element is in

but, like I said, I'm not a native english speaker, I don't understand OP's problem very well and the task generally leaves some questions unanswered

oh, and you're only overwriting the same position, not summing it up, but changing

E[i][j] = E[x][y];
to
E[i][j] += E[x][y];
would probably fix it.

again, we don't even know if we're supposed to reset E[i][j] before accessing it again to be a part of the sum or if we should leave it as is to sum it up. if E[i][j] is a huge negative number, we'll just end up with a negative number again. if all values are negative, the numbers will just get smaller and smaller ...

9 years ago*
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Greffin28

lol yeah, me neither (i meant native speaker of course)*. But, your solution should give the basic idea for it
Edit: Oh yeah! lol forgot the plus sign thanks :D

9 years ago*
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Greffin28

Man, trial and error with the debugger is easier than writing it manually xD

9 years ago
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prus666

Uhm, aren't you supposed to do your homework by yourself?

9 years ago
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EndLau

It clearly says that YOU personally have to help me with it. There's even a stamp with a goose next to it

9 years ago
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EndLau

That's what I'm up to right now:

const int m = 4;
const int n = 3;

int main()
{
ofstream fr("asd.txt");
int E[m][n];
for (int i = 0; i < m; i++)
{
for (int j = 0; j < n; j++)
{
if (E[m][n] < 0)
{
E[m][n] = (i + j);
}
}
cout << E[m][n] <<endl;
fr << E[m][n] <<endl;
}
fr.close();
_getch();
}

9 years ago
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TheDopefish

you're never assigning values to your array in the first place, so how would you know what originial values you're starting with and what result you're expecting?

9 years ago
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Greffin28

I suggest you change your if code as it's checking the same value over and over again, look at TheDopefish* comment above.. Might help not sure though.
Edit: Oh, and initialize your arrays first, by the way like what TheDopefish said.

9 years ago*
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EndLau

like this? int E[m][n] = { { 2, 3 }, { -3, 4 }, { 0, 0 }, { 2, -2 } };

9 years ago
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Greffin28

As far as i can remember it yeah

9 years ago
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