how does it effect my code?

actually i was learning SPOOLING technique.

How to know that weather we have to use pragma or ": :"

to include header file only one time in one compilation unit

ok and if we use fork inside the code then ? will the clone again read the header file

they are two different things. https://gcc.gnu.org/onlinedocs/cpp/Pragmas.html https://docs.microsoft.com/en-us/cpp/preprocessor/pragma-directives-and-the-pragma-keyword https://en.wikipedia.org/wiki/Pragma_once

what is fork and clone? linux system calls?

man fork

ok and if we use fork inside the code then ? will the clone again read the header file

(Thanks for the reply but I eventually ditched ncurses as I got my C snippet working)

fork is a runtime thing. including a header file is a compile time thing

someone can tell me how can I sum each 3 element of an array in c?

so the child will again read the header file

someone can tell me how can I sum each 3 element of an array in c?

almost always you should use pragma once. however its compiler extension

so the child will again read the header file

int res = 0; for (int *element = numarray; element != numarray + 3; element++) { res += *element; }

forget about child process, fork and clone consider: header.h void foo(); header2.h #include "header.h" header3.h #include "header.h" main.cpp #include "header2.h" #include "header3.h" int main() { } Problem: header.h is included two times in main.cpp. to fix this we add #pragma once to header.h

this would be off-topic but can someone tell me a group where I can ask questions regarding computer architecture, OS, DBMS?

please someone?

[1][2][3] [4][5][6] [7][8][9] , they are all element of an array I have to sum each 3 element for example and divide per 3

It's not hard, find it out yourself 😉

I'm trying, It's a 2 dimensional array for (i = 0; i < raw; i++) for(j = 0; j < column; j++ ) matrix[i][j] = matrix[i][j] + matrix[i][j+1] + matrix[i][j+2] but It works just for first 3 elements not others.

yes, because you add indices 0,1,2, then 1,2,3, then 2,3,4 and so on

I tried replace 1 and 2 with a=0, b=1 and c=2. And c +=3; a +=3; b+=3; after each time of loop but doesn't work

that's one option to solve it, have you changed your condition in the for loop? you're reading three times the elements now

yep I've put j < column /3;

then it should work, can you share the code?

then it should work, can you share the code?

where is the += 3 ? you basically haven't changed anything since you don't change a, b and c

I'm trying, It's a 2 dimensional array for (i = 0; i < raw; i++) for(j = 0; j < column; j++ ) matrix[i][j] = matrix[i][j] + matrix[i][j+1] + matrix[i][j+2] but It works just for first 3 elements not others.

small question, do you want it like this -> a[0][0] + a[0][1] + a[0][2], a[0][3] + a[1][0] + a[1][1]? (first row is exhausted at a[0][3])

nope, I'have to sum first 3 element and then second 3 element . . . in each raw

okay so if there is an extra element left in the row we should just discard it and proceed to next row?

where is the += 3 ? you basically haven't changed anything since you don't change a, b and c

for example I have to sum 255+0+0 and 0+255+0 and 0+0+255 in first raw and in second 255+255+0 and 255+255+255 and 0+0+0

#include <iostream> int main() { unsigned N,K; std::cin >> N>> K; int i = 1; int count = 0; while ( i <= N){ int x; std::cin >> x; if( x>=123){ count ++; } if (cout== K) std::cout <<"YES"; else std::cout << "NO"; } }

for (size_t i = 0; i != ROW; ++i) { for (size_t j = 0; j < COL; j += 3) { a[i][j] = a[i][j] + a[i][j + 1] + a[i][j + 2]; } }

for (size_t i = 0; i != ROW; ++i) { for (size_t j = 0; j < COL; j += 3) { a[i][j] = a[i][j] + a[i][j + 1] + a[i][j + 2]; } }

#include <iostream> int main() { int i; std::cin >> i; do { std::cin >>i; i+=1; } while (i!=0); }

why you do i+1? you can have 2 variables here, one for sum and one for value, and I guess you don't need the first std::cin>>i; line

It is required to write a program that will receive an integer in the entry until 0 is entered. And the sum of the imported numbers will be displayed. It is forbidden to use mass.

#include <iostream> auto main() -> int { long i=0; int input=-1; for(;input!=0;) { std::cin >>input; i+=input; } std::cout << i; }

do {...} while(...); loop would look more clear as for my taste

#include <iostream> int main() { int value; int sum = 0; do { std::cin >> value; sum += value; } while (value!=0); }

Maximum run time exceeded

Show the question

It is required to write a program that will receive an integer in the entry until 0 is entered. And the sum of the imported numbers will be displayed. It is forbidden to use mass.