Problem with neighboring positions in C++ arrays

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#include <iostream>

using namespace std;

int main(){
    int myVector[] = {2,6,4,1,9,5,7,3,8,0};
    int tamanhoVetor = sizeof(myVector)/sizeof(myVector[0]);

    //Imprime
    for (int i=0; i<tamanhoVetor-1; i++){
        cout << myVector[i+1] << ", ";
    }

    return 0;
}

The expected would be:

6, 1, 5, 3, 0

but he returns:

6, 4, 1, 9, 5, 7, 3, 8, 0

I did not understand why it occurs this, I tried to do the same thing in Python, only that the same problem occurs. Probably the mistake is in my logic.

c c++ algorithm loop

  • The variable sizeVetor is with the value 10, its starts at 0 and always prints the loop plus one, so you end up printing all the values of your vector, except for the first position.

  • If you want to skip numbers in the for, you can increase the increment of the same, increase for example two each cycle: for (int i=0; i<sizeVetor-1; i+=2)

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2 answers

1

A pity to be using C in a C++ code, should not do this. C++ to use array or vector and not the pointer that simulates array of C. If you made C++ you wouldn’t have this error.

Really your logic is wrong, you should jump 2 by 2 and not jump 2 by 1 and add 1 like you did, and simplify would look like this:

#include <iostream>
using namespace std;

int main() {
    int myVector[] = {2,6,4,1,9,5,7,3,8,0};
    for (int i = 0; i < sizeof(myVector) / sizeof(myVector[0]); i += 2) cout << myVector[i+1] << ", ";
}

Behold working in the ideone. And in the repl it.. Also put on the Github for future reference.

0

One solution is to increment before printing. The addition operation within the vector did not work. As below:

#include <iostream>

using namespace std;

int main(){
    int myVector[] = {2,6,4,1,9,5,7,3,8,0};
    int tamanhoVetor = sizeof(myVector)/sizeof(myVector[0]);

    //Imprime
    for (int i=0; i<tamanhoVetor-1; i++){
        i++;
        cout << myVector[i] << ", ";
    }

    return 0;
}

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