Zbrajanje dijagonala u matrici

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>
#include <math.h>


int main(){

    int mat[5][5],n,i,j,sumG=0,sumS=0, polje[10], brojac=0,manji,veci;
    float avgG, avgS;
    do{

        scanf(" %d", &n);
        if (n<1 || n>5)
        printf("Dimenzije matrice ne odgovaraju rasponu!\nPonovo unesite dimenziju.\n");

    }while (n<1 || n>5);


    for(i=0;i<n;i++){
        for(j=0;j<n;j++){

            scanf(" %d", &mat[i][j]);
        }
    }
    printf("Ispis matrice:\n");
    for(i=0;i<n;i++){
        for(j=0;j<n;j++){

            printf("%d\t", mat[i][j]);
        }
        printf("\n");
    }

    for(i=0;i<n;i++){
        for(j=0;j<n;j++){
            if (i==j){
                sumG+=mat[i][j];
            }
            if (i+j==n-1)
                sumS+=mat[i][j];
        }
    }

    avgG=(float)sumG/n;
    avgS=(float)sumS/n;
    printf("\nProsjek glavne dijagonale: %.2f\n", avgG);
    printf("Prosjek sporedne dijagonale: %.2f\n", avgS);
    if(avgS<=avgG){
        manji=avgS;
        veci=avgG;
    }
    else{
        manji=avgG;
        veci=avgS;
    }

    for(i=0;i<n;i++){
        for(j=0;j<n;j++){

                if(mat[i][j]>manji && mat[i][j] <=veci){
                    polje[brojac]=mat[i][j];
                    brojac++;
                }

        }
    }
    printf("Ispis 1D polja:\n");

    for(i=0;i<brojac;i++){
            if(i!=brojac-1){
        printf("%d, ", polje[i]);
            }
            else printf("%d", polje[i]);
    }


return 0;
}