How do you write a c program sum of all elements from a two dimensional (2D) array?

Answer 1

#include #include voidmain() { int a[10]; int i,sum=0; int *ptr; printf("Enter 10 elements:n"); for(i=0;i<10;i++) scanf("%d",&a[i]); ptr = a; /* a=&a[0] */ for(i=0;i<10;i++) { sum = sum + *ptr; //*p=content pointed by 'ptr' ptr++; } printf("The sum of array elements is %d",sum); }

Answer 2

#include<stdio.h>

#include<conio.h>

void main()

{

int arr[50][50];

int i,j,n1,n2;

printf("enter size of array no of rows-");

scanf("%d",&n1);

printf("enter size of array no of columns-");

scanf("%d",&n2);

for (i=0;i<n1;i++)

{

for (j=0;j<n2;j++)

{

printf("enter elemnt");

scanf("%d",&arr[i][j]);

}

}

getch();

}

Answer 3

#include<stdio.h>

#include<assert.h>

/* sum the given 2D array */

int sum_array (const int* arr, const unsigned int rows, const unsigned int cols) {

unsigned int x, y;

int sum;

sum = 0;

if (!arr) return sum;

for (x=0; x<rows; ++x)

for (y=0; y<cols; ++y)

sum += arr[x*cols+y];

return sum;

}

int main (void) {

const unsigned int rows=5;

const unsigned int cols=6;

int sum;

int a[rows][cols];

unsigned int x, y;

for (x=0; x<rows; ++x)

for (y=0; y<cols; ++y)

a[x][y] = (x+1)*(y+1);

sum = sum_array ((int*)a, rows, cols);

printf ("The sum of the array is: %d\n", sum);

assert(sum == 315);

return 0;

}

Answer 4

If the arrays are fixed-length, summing them is reasonably trivial:

int a[5] = {1, 2, 3, 4, 5};

int b[5] = {10, 20, 30, 40, 50};

int c[5];

for (unsigned i=0; i<5; ++i) {

c[i] = a[i] + b[i];

}

Note that a, b, and c must all be of the same size. With fixed-length arrays it's a good idea to store the size in a constant variable:

const unsigned size = 5;

int a[size] = {1, 2, 3, 4, 5};

int b[size] = {10, 20, 30, 40, 50};

int c[size];

for (unsigned i=0; i<size; ++i) {

c[i] = a[i] + b[i];

}

Summing variable-length arrays is a bit more complex, but we can simplify with a function:

int* sum (int* a, int* b, const unsigned size) {

int* p = malloc (size * sizeof (int));

if (p == NULL) return NULL; // sanity check!

for (unsigned i=0; i<size; ++i) {

p[i] = a[i] + b[i];

}

return p;

}

The sanity check is necessary to ensure the memory was actually allocated. If successful, the caller is responsible for releasing the allocated memory:

void f (int* a, int* b, const unsigned size) {

int* p = sum (a, b, size);

if (p == NULL) return; // sanity-check!

// ...

free (p);

}