Output not correct for my C++ program - c++

Question

So, I have the following problem:
From the file tabl.in a number n will be read (n<=50).
After that a square array with n rows and n columns will be read; all the numbers in the array will be composed by a maximum of 2 digits each.
Shown in the file tabl.out, the modulo between the sum of numbers found on the second diagonal of the array and 10, if the sum is palindrome (true=1, false=0), and the arithmetic mean of elements situated below of the main diagonal.
Will be writing functions for:
reading the array
calculation of the operation sum of secondary diagonal%10
checking if the previous result it is palindrome
calculation of the arithmetic mean below main diagonal
Example:
tabl.in:
4
5 8 2 12
1 0 3 16
1 2 1 11
5 7 2 19
tabl.out:
2 1 3
where
(12+3+2+5)%10 = 22%10 = 2
22 is palindrome = 1
1+2+2+1+7+5 = 18, 18/6=3
My code so far is:
#include <fstream>
using namespace std;
ifstream fin("tabl.in");
ofstream fout("tabl.out");
void readn(int Arr[][51], int n) {
for (int i = 1; i <= n; i++)
for (int j = 1; j <= n; j++)
fin >> Arr[i][j];
}
int sumsec(int Arr[][51], int n) {
int s = 0;
float r;
for (int i = 1; i <= n; i++)
s = s + Arr[i][n - i + 1];
r = s % 10;
return r;
}
void pald(int Arr[][51], int n) {
int s = 0, pal = 0;
for (int i = 1; i < n; i++)
s = s + Arr[i][n - i + 1];
while (s != 0) {
pal = pal * 10 + s % 10;
s = s / 10;
}
if (pal == s)
fout << "1 ";
else
fout << "0 ";
}
int ambmd(int Arr[][51], int n) {
int s = 0, k;
float ame;
for (int i = 2; i <= n; i++) {
for (int j = 1; j <= i - 1; j++) {
s = s + Arr[i][j];
k++;
}
}
ame = s / k;
return ame;
}
int main() {
int Arr[51][51], n;
float r, ame;
fin >> n;
readn(Arr, n);
r = sumsec(Arr, n);
fout << r << " ";
pald(Arr, n);
ame = ambmd(Arr, n);
fout << ame;
}
But I have an issue with the palindrome() function: my output file will have 2 0 3 written to it for the given array from the example, instead of 2 1 3. What am I doing wrong?

Answer 1

Your pald function would work, if you compute s the same way as you do in sumsec and if s would still contain the sum, after you compute pal.
In your case, while (s != 0) {...}, followed by if (pal == s) {...} could be re-written as if (pal == 0), which is clearly not the intended solution. Just save your sum before computing pal, then compare with the saved sum.
Also, change your loop condition for computing s to for (int i = 1; i <= n; i++).
int s = 0, pal = 0, sum = 0;
for (int i = 1; i <= n; i++)
s = s + Arr[i][n - i + 1];
sum = s;
while (s != 0) {
pal = pal * 10 + s % 10;
s = s / 10;
}
if (pal == sum)
fout << "1 ";
else
fout << "0 ";
You should also consider the various comments for code improvements, like not re-computing the sum in the pald function.