Program 1

#include<iostream>

using namespace std;

int main() {

int n = 5;

int p = 1;

int input;

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

 cout << "input number " << i + 1 << endl;

 cin >> input;

 p *= input;

}

cout << p << endl;

cin >> n; // for pause

return 0;

}

Program 2

#include<iostream>

using namespace std;

int main() {

int n;

int p = 0;

int input;

cout << "n = " << endl;

cin >> n;

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

 cout << "input number " << i + 1 << endl;

 cin >> input;

 p += input;

}

cout << p << endl;

cin >> n; // for pause

return 0;

}

Program 3

#include<iostream>

using namespace std;

int main() {

int n;

int count = 0;

int input;

cout << "n = " << endl;

cin >> n;

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

 cout << "input number " << i + 1 << endl;

 cin >> input;

  if(input < 0) count ++;

}

cout << count << endl;

cin >> n; // for pause

return 0;

}