error: subscripted value is neither array nor pointer nor vector

This error message occurs when you try to use the subscript operator ([ ]) on a variable that is not an array, pointer, or vector.

For example, if you try to access a single character in a string using the subscript operator, but you forget to declare the string as an array or pointer, you will get this error.

Here's an example of incorrect code that would trigger this error:

int main() {
    int x = 5;
    x[0] = 10;
    return 0;
}

In this example, we are trying to use the subscript operator on an integer variable "x", which is not an array, pointer, or vector. To fix this error, we need to declare "x" as an array or pointer first, like this:

int main() {
    int x[5] = {1, 2, 3, 4, 5};
    x[0] = 10;
    return 0;
}

Now we have declared "x" as an array, and we can use the subscript operator to access its elements.