Part array sum(down)

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#include <stdio.h>
#include <math.h>
#define SIZE 10

//https://otvet.mail.ru/question/211269192
//for an array - does sum for part of it, down from 2 diagonales

void pop_arr(int *,int);
void pr_arr(int *,int);

int main()
{
    int i,j,arr[SIZE][SIZE],total,step = 0;
    total = 0;

    for(i=0;i<SIZE;i++)
    {
        for(j=0;j<SIZE;j++)
        {
            arr[i][j]= SIZE*i+j;
            printf("%d\t",arr[i][j]);
        }
        printf("\n");
    }

    for(i = SIZE/2;i<SIZE;i++)
    {
        for(j = 0;j<SIZE;j++)
        {
            if(j>=SIZE/2-step&&j<=SIZE/2+step)
                total+=arr[i][j];
        }
        printf("\n");
        step++;
    }
    printf("total is %d now\n",total);

    return 0;
}