Question

I would like to have a dynamic character array who’s length equals the loop iteration.

char* output;
for (short i=0; i<2; i++){
    output = new char[i+1];
    printf("string length: %d\n",strlen(output));
    delete[] output;
}

But strlen is returning 16, where I would expect it to be 1 and 2.

Answer 1

The newly allocated memory pointed to by output is not initialized: it may have any contents.

strlen requires its argument to be a pointer to a null-terminated string, which output is not, because it hasn’t been initialized. The call strlen(output) causes your program to exhibit undefined behavior because it reads this uninitialized memory. Any result is possible.