E1
#include<iostream>
using namespace std;

const int MAX = 100;

void nhap(int n, int a[][MAX]){
	for(int i=0; i<n; i++){
		for(int j=0; j<n; j++){
			cout << "a[" << i << "][" << j <<"] = ";
			cin >> a[i][j];
		}
	}
}

bool isSD(int c){
	return c > 0;
}

int dem(int n, int a[][MAX], int k){
	int dem = 0;
	for(int j=0; j<n; j++){
		if(isSD(a[k][j])) dem++;
	}
	return dem;
}

int main(){
	int n, k;
	int a[100][MAX];
	cout << "Nhap n = "; cin >> n;
	nhap(n,a);
	cout << "Nhap hang k = "; cin >> k;
	if(dem(n,a,k) == 0){
		cout << "Khong co so duong nao o hang " << k << ".";
	}else{
		cout << "Co " << dem(n,a,k) << " so duong o hang " << k << ".";
	}
}

E2
#include<iostream>
using namespace std;

const int MAX = 100;

void nhap(int n, int a[][MAX]){
	for(int i=0; i<n; i++){
		for(int j=0; j<n; j++){
			cout << "a[" << i << "][" << j <<"] = ";
			cin >> a[i][j];
		}
	}
}

bool isCP(int c){
	if(c<0) return false;
	if(c==0 || c==1) return true;
	for (int i=2; i<=(c/2); i++){
		if(i*i == c) return true;
	}
	return false;
}

long tongCP(int n, int a[][MAX]){
	long tong = 0;
	for(int i=0; i<n; i++){
		for(int j=0; j<n; j++){
			if(isCP(a[i][j])){
				tong += a[i][j];
			}
		}
	}
	return tong;
}

int main(){
	int n, k;
	int a[100][MAX];
	cout << "Nhap n = "; cin >> n;
	nhap(n,a);
	if(tongCP(n,a) == 0){
		cout << "Khong co so chinh phuong nao trong ma tran.";
	}else{
		cout << "Tong cac so chinh phuong trong ma tran la: " << tongCP(n,a);
	}
}