位的位移位数组为Int变量

Question

So I'm not sure if this is the easiest way to accomplish what my end goal is, so if anyone has a better suggestion, feel free to throw it at me. I've tried searching both on here, and with Google, but I can't seem to figure out how to do this.

I have an array of int values: int bitVal[8]

In my program, each of these values is 1 bit, within a byte. I need to create a loop which goes through each value, and bit shift the value into the int variable.

I tried this as a simple test:

int t = 0;
int e = 1;
for(int i = 0; i < 3; i++) {
    t <<= e;
    printf("%d\n", t);
}

Now I know that if I had a variable that had a byte value of 0000 0010 and I do var <<= 1; the result will be 0000 0100 . Is there a way to set it so the shifted bit is a 1 instead of a 0?

Answer 1

You're probably overthinking it. You can shift in one bit at a time, regardless whether it is a 0 or 1. All it needs is a loop such as this:

result = 0;
for (i=0; i<8; i++)
{
    result = (result<<1) | bitVal[i];
}

Answer 2

Is there a way to set it so the shifted bit is a 1 instead of a 0?

No, not as such. Instead, what you do is shift the target value to make room, and then combine with the value you want to add. For example, if x is your accumulation variable and y contains a value that you are certain is either 0 or 1, then you might do this:

x = (x << 1) | y;