Summarise positive in even rows & negative in neven rows

#include <stdio.h>
#include <string.h>
#include <math.h>
#define SIZE 4

//not happy about variable names
//seems ok function names, but then good name for var should be
//total_positive_even, total_positive_neven-seems too long!
//summarise : in all even rows – all positive elements, in all non even rows – all //negative
void pop_arr(int s,int a[SIZE][SIZE]);
void pr_arr(int s,int a[SIZE][SIZE]);
int sum_pos_even(int s,int a[SIZE][SIZE]);
int sum_neg_neven(int s,int a[SIZE][SIZE]);


int main()
{
    int p_e,n_ne,arr[SIZE][SIZE];//positive even, negative not even
    pop_arr(SIZE,arr);
    pr_arr(SIZE,arr);
    p_e  = sum_pos_even(SIZE,arr);
    n_ne = sum_neg_neven(SIZE,arr);
    printf("positive even %d, negative not even %d\n",p_e,n_ne);

    return 0;
}
void pop_arr(int s,int a[SIZE][SIZE])
{
    int i,j;
    for(i=0;i<s;i++)
    {
        for(j=0;j<s;j++)
            a[i][j]= rand()%20-10;
    }
}

void pr_arr(int s,int a[SIZE][SIZE])
{
    int i,j;
    for(i=0;i<s;i++)
    {
        for(j=0;j<s;j++)
            printf("%d\t",a[i][j]);
        printf("\n");
    }
}

int sum_pos_even(int s,int a[SIZE][SIZE])
{
    int i,j,sum = 0;
    for(i=0;i<s;i+=2)
    {
        printf("i is %d\n",i);
        for(j=0;j<s;j++)
           {
               if(a[i][j]>0)
                  sum+=a[i][j];
           }
    }
    return sum;
}

int sum_neg_neven(int s,int a[SIZE][SIZE])
{
    int i,j,sum = 0;
    for(i=1;i<s;i+=2)
    {
        for(j=0;j<s;j++)
            if(a[i][j]<0)
                sum+=a[i][j];
    }
    return sum;
}