C++ ONLY

Write a program that edits an image file, turning it into grayscale.

Replace each pixel with a pixel that has the same grayness level for the blue, green, and red component. The grayness level is computed by adding 30 percent of the red level, 59 percent of the green level, and 11 percent of the blue level. (The color-sensing cone cells in the human eye differ in their sensitivity for red, green, and blue light.)

C++ ONLY