Question

Could somebody be kind to explain why in the world this gives me a segmentation fault error?

#include <vector>
#include <iostream>

using namespace std;

vector <double>freqnote;

int main(){

freqnote[0] = 16.35;

cout << freqnote[0];

return 0;
}

I had other vectors in the code and this is the only vector that seems to be giving me trouble.

I changed it to vector<int>freqnote; and changed the value to 16 and I STILL get the segmentation fault. What is going on?

I have other vector ints and they give me correct results.

Answer 1

You’re accessing vector out of bounds. First you need to initialize vector specifying it’s size.

int main() {
    vector<int> v(10);
    v[0] = 10;
}