Discuss C++ Institute CPP Exam Topic 9 Question 110

What happens when you attempt to compile and run the following code?

#include

using namespace std;

int main() {

int t[] = { 1, 1, 2, 2, 3, 3, 4, 4, 5, 5 };

string s[] = { "one", "one", "two", "two", "three","three", "four", "four", "five", "five"};

map m;

for (int i = 0; i < 10; i++) {

m.push_back(pair(t[i], s[i]));

}

for (map::iterator i = m.begin(); i != m.end(); i++) {

cout << i?>first << " ";

}

return 0;

}

Aprogram outputs: 1 2 3 4 5

Bcompilation error

Cprogram outputs: 1 1 2 2 3 3 4 4 5 5

Dprogram outputs: one two three four five

Eprogram outputs: one one two two three three four four five five

Suggested Answer: B

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26 comments · newest first

Nathalie 10 months ago

Wait, are you sure? I thought it would just ignore duplicates.

Ronna 10 months ago

Totally agree, maps use insert, not push_back!

Haydee 10 months ago

Looks like a compilation error due to push_back on map.

Gracie 10 months ago

I thought it would output 1 2 3 4 5, but now I'm confused!

Daniela 11 months ago

Definitely a compilation error, no doubt about it.

Cordelia 11 months ago

I remember that the `map` should store unique keys, so I guess it will output "one two three four five" based on the last occurrences.

Bea 11 months ago

I practiced a similar question, and I think the iterator part might have a syntax issue with `i?>first`.

Mattie 11 months ago

I’m not sure, but I feel like the output should be unique keys, so maybe it will print "1 2 3 4 5"?

Veronika 11 months ago

I think there’s a compilation error because I remember that `map` doesn’t have a `push_back` method.

Amos 12 months ago

Ah, I see the problem now. The map is going to store each key-value pair, but since the keys are duplicates, it will only output the unique keys.

Vinnie 12 months ago

I'm a bit confused about how the map is being populated. Shouldn't we be using the map.insert() method instead of push_back()?

Virgina 12 months ago

I'm pretty confident I know the answer to this one. The map will automatically sort the keys, so the output should be the unique numbers in order.

Deonna 1 year ago

Okay, I think I see the issue. The map.push_back() method doesn't exist, so that's going to cause a compilation error.

Felicitas 1 year ago

Hmm, this looks tricky. I'll need to carefully read through the code and think about how the map data structure works.

Sheron 1 year ago

I'm going with option E. The map will preserve the order of the elements, so it'll print out all the values.

Evan 1 year ago

↳ replying to Sheron

Yes, I agree. The program will output: one one two two three three four four five five.

Princess 1 year ago

↳ replying to Sheron

I think it's option E because the map will keep the order of the elements.

Dana 1 year ago

Option D seems like the way to go. The map should store the unique keys and their corresponding values.

Carissa 1 year ago

Haha, option C would be hilarious! The map just prints out the keys without caring about the values. What a mess!

Loren 1 year ago

I believe the error is due to the use of push_back with a map.

Annett 1 year ago

I agree with Brock, there seems to be an issue with the code.

Providencia 1 year ago

I think the correct answer is B. The code has a compilation error because you can't use push_back() with a map.

Octavio 1 year ago

The output should be option A, since the map will automatically handle the duplicate keys and only store unique values.

Scot 1 year ago

↳ replying to Octavio

B) compilation error

Scot 1 year ago

↳ replying to Octavio

B) compilation error

Brock 1 year ago

I think the answer is B) compilation error.

C++ Institute CPP Exam - Topic 9 Question 110 Discussion