value_stack::push_object

## `value_stack::push_object`

Push an object onto the stack.

### Synopsis

    void
    push_object(
        std::size_t n);

### Description

This function pushes an `object` value onto the stack. The object is formed by first popping the top `n` key/value pairs from the stack. If the stack contains fewer than `n` key/value pairs, or if any of the top `n` key/value pairs on the stack does not consist of exactly one key followed by one value, the behavior is undefined.

| A key/value pair is formed by pushing a key, and then pushing a value.

### Example

The following code creates an object on the stack with a single element, where key is "x" and value is true:

    value_stack st;

    // reset must be called first or else the behavior is undefined
    st.reset();

    // Place a key/value pair onto the stack
    st.push_key( "x" );
    st.push_bool( true );

    // Replace the key/value pair with an object containing a single element
    st.push_object( 1 );

    // Pop the object from the stack and take ownership.
    value jv = st.release();

    assert( serialize(jv) == "{\"x\",true}" );

    // At this point, reset must be called again to use the stack

### Duplicate Keys

If there are object elements with duplicate keys; that is, if multiple elements in an object have keys that compare equal, only the last equivalent element will be inserted.

### Exception Safety

Basic guarantee. Calls to `memory_resource::allocate` may throw.

### Parameters

Name | Description
--- | ---
`n` | The number of key/value pairs to pop from the top of the stack to form the array.

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