Conversion From Gray scale to RGB colormap

Hello, I am trying to convert images from gray scale to RGB. Firstly, I tried it for the jet colormap, but I would like to do this for other possible colormaps which MATLAB has. I imported the 'car1.jpg' image and converted via these lines:

indexedImage = imread('car1.jpg');
Gray_Image= indexedImage(:,:,1)*0.299+indexedImage(:,:,2)*0.587+indexedImage(:,:,3)*0.114;

Then I gave "Gray_Image" variable to my function "gray_to_jet" to convert RGB. Although output seemed like "jet", there are differences between MATLAB's jet colormap. How can I exactly map the values like MATLAB? I am new to image processing, so any help including theoritical appreciated. Here is my function:

function [converted_image,Elapsed_time] = gray_to_jet(varargin)
input_image = varargin{1};
[row_number, column_number] = size(input_image);
C = uint8(255*colormap('jet')); % Convert 0-1 numbers in colormap to 0-255 and uint8.
converted_image = zeros(row_number, column_number, 3);
for idx = 1:row_number
    for jdx =1:column_number
        colormap_row= double(input_image(idx, jdx) ) + 1;
        new_red_pixel = C(colormap_row, 1);
        new_green_pixel = C(colormap_row, 2);
        new_blue_pixel = C(colormap_row, 3);
        converted_image(idx, jdx, 1) = new_red_pixel;
        converted_image(idx, jdx, 2) = new_green_pixel;
        converted_image(idx, jdx, 3) = new_blue_pixel;
    end
end
end

Answer 1

[Image Analyst]

Don't so it like that. Simply use ind2rgb()

rgbImage = ind2rgb(indexedImage, cmap);

[Berkay Yaldiz]

Thank you for your answer, actually I need to do it this conversion in C by hand because it is a school project and I just figured it out the problem I think, I had to convert result to uint8 datatype.

[Image Analyst]

Since it's no longer a MATLAB question, you'd be better off asking in a C language question and answer forum.