Update example to include setting and getting ndarray elements

Author: kgryte

lib/node_modules/@stdlib/ndarray/ctor/examples/c/example.c

@@ -100,6 +100,41 @@ int main() {
 	printf( "byteLength = %lld\n", stdlib_ndarray_bytelength( x2 ) );
 	printf( "ltr = %u\n", stdlib_ndarray_dtype_char( stdlib_ndarray_dtype( x2 ) ) );
 
+	// Set values in the underlying byte array:
+	int64_t sub[] = { 0 };
+	void *ptr = stdlib_ndarray_get_ptr( x2, sub );
+	if ( ptr == NULL ) {
+		printf( "Unable to resolve data pointer.\n" );
+		exit( 1 );
+	}
+	*(double *)ptr = 1.0;
+
+	sub[ 0 ] = 1;
+	ptr = stdlib_ndarray_get_ptr( x2, sub );
+	if ( ptr == NULL ) {
+		printf( "Unable to resolve data pointer.\n" );
+		exit( 1 );
+	}
+	*(double *)ptr = 2.0;
+
+	sub[ 0 ] = 2;
+	ptr = stdlib_ndarray_get_ptr( x2, sub );
+	if ( ptr == NULL ) {
+		printf( "Unable to resolve data pointer.\n" );
+		exit( 1 );
+	}
+	*(double *)ptr = 3.0;
+
+	for ( int64_t i = 0; i < stdlib_ndarray_length( x2 ); i++ ) {
+		ptr = stdlib_ndarray_iget_ptr( x2, i );
+		if ( ptr == NULL ) {
+			printf( "Unable to resolve data pointer.\n" );
+			exit( 1 );
+		}
+		const double v = *(double *)ptr;
+		printf( "data[%lld] = %f\n", i, v );
+	}
+
 	// Free the allocated memory:
 	free( x2 );
 }