Can someone give me some idea on how to store data in 'bit's.
I am currently working on bit operators and have hit a snag.
For example there a question in my c reference book:
Store rainbow colors in a char variable named color.
When user presses 0 violet appears on screen,press 1 indigo appears on screen and so on..
The easy way is to have a string array and store all the data.
But how to achieve this using/manipulating bit?
Thanks in advance,
Arun
You need to view a bit as something which is either turned on or off, not in terms of a colour. So, if you want a set of bits to represent colour mixing, one bit might indicate if the colour includes a violet component, another bit might indicate if it contains an indigo component, etc. Then you just need to set a way to turn relevant bits on and off. To render a colour, naturally, you need to determine whether each bit is on or off and (if multiple bits are set) work out what that means (eg what colour do you want rendered if bits for both indigo and violet are turned on?).
The various bitwise operations (>>, <<, &, |, ~, and ^) in combination can be used to construct techniques to turn particular bits on and off, or detect if they are set. I won't tell you how, since you will learn more by nutting that out for yourself.
Does this help?
Code:// assign colour bits #define RED (1<<0) #define ORANGE (1<<1) #define YELLOW (1<<2) // add red to the colour colour |= RED; // is yellow present? if ( colour & YELLOW ) // no more orange colour &= ~ORANGE
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This sounds to me more like a palette approach is asked for than a flag per colour. I'd therefore just use a lookup table.
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Whats a lookup table?Originally Posted by iMalc
So basically we don't or rather cannot assign values or data to bits.
Just toggle between 0 and 1 and do some operation if any condition is satisfied?
Check my code please:
Code:#include <stdio.h> #include <stdlib.h> int main() { int num=0; char color; color = 64; char colormask; colormask = 64; printf("Enter a number."); scanf("%d",&num); switch(num) { case 0: //red //colormask = 64; //1000000 if((color & colormask)) printf("Red"); break; case 1: //orange colormask = 32; //100000 or colormask=colormask >> 1 color = color >> 1; //printf("%d",color); if(color & colormask) printf("Orange"); break; case 2: //yellow colormask = colormask >> 2; // 16 color = color >> 2; if(color & colormask) printf("yellow"); break; } return 0; }
An array or similiar construct where the key value that you are searching for is the index, and the corresponding value is the value of the array element.
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E.g. this:Code:const char *colour[] = {"red", "orange", "yellow", etc etc}; printf(colour[num]);
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That's what i meant by using the string array in my first post.
Also
i did not find the need for doing this operation as i shift color to what ever value i want in every case.Code:// add red to the colour colour |= RED;
Which proves to be more efficient?shifting(>>) color for a case or adding (|) to the existing color every time?
