Backpacking

#include <string>

using namespace std;

int main(int argc, char* argv[])
{
    string a = argv[1];
    string b = argv[2];
    int ia = stoi(a);
    int ib = stoi(b);
    int sum = ia + ib;
    printf("%d\n\r", sum);
    return sum;
}

Test 1

Verdict: RUNTIME ERROR

terminate called after throwing an instance of 'std::logic_error'
  what():  basic_string: construction from null is not valid

Test 2

Verdict: RUNTIME ERROR

terminate called after throwing an instance of 'std::logic_error'
  what():  basic_string: construction from null is not valid

Test 3

Verdict: RUNTIME ERROR

terminate called after throwing an instance of 'std::logic_error'
  what():  basic_string: construction from null is not valid

Test 4

Verdict: RUNTIME ERROR

terminate called after throwing an instance of 'std::logic_error'
  what():  basic_string: construction from null is not valid