What is the oxidation number of C in formaldehyde, ${\mathrm{CH}}_2\mathrm{O}$?

The structure of formaldehyde, CH2O with oxidation  number is shown below.

$\underset{+1}{\mathrm{H}}-\underset{0}{\overset{\stackrel{{\mathrm{O}}^{-2}}{\overline{)\overline{) }}}}{\mathrm{C}}}-\underset{+1}{\mathrm{H}}$

Here, the oxidation number of C in formaldehyde, ${\mathrm{CH}}_2\mathrm{O}$ is 0.