add text or change text inside of richtextbox programmatically?

[poringgunner]

(abad_string.cpp To abad_string.cpp : 0.00%
Data Type: 0.00%
Control Structure: 0.00%
0 VARIABLES are the same

abad_string.cpp To Alarcon_string.cpp : 81.03%
Data Type: 100.00%
Control Structure: 0.00%
2 VARIABLES are the same

)

(Alarcon_string.cpp To abad_string.cpp : 81.03%
Data Type: 100.00%
Control Structure: 0.00%
2 VARIABLES are the same

Alarcon_string.cpp To Alarcon_string.cpp : 0.00%
Data Type: 0.00%
Control Structure: 0.00%
0 VARIABLES are the same

)



the selected word is regarding into the user input.
i want to change the selected word example this is my selected word.. "(abad_string.cpp"

then i want it to change like this..



(abad_string.cpp To abad_string.cpp : 0.00% // i want this to change into this.... "+(abad_string.cpp ",... only add "+" in the start of the slectected word.
Data Type: 0.00%
Control Structure: 0.00%
0 VARIABLES are the same

abad_string.cpp To Alarcon_string.cpp : 81.03%
Data Type: 100.00%
Control Structure: 0.00%
2 VARIABLES are the same

)

(Alarcon_string.cpp To abad_string.cpp : 81.03%
Data Type: 100.00%
Control Structure: 0.00%
2 VARIABLES are the same

Alarcon_string.cpp To Alarcon_string.cpp : 0.00%
Data Type: 0.00%
Control Structure: 0.00%
0 VARIABLES are the same

)