如果在循环中数组的某个元素上，请执行X动作

Question

Is there a way to see that, if a loop is on a certain element of an array, to do a specific action?

Say that if I'm on the first element of an array in a loop, set a flag to false?

ex)

        int carry = 1;
    int arraySum[] = new int[NUM_DIGITS];
    boolean carryFlag = false;
    for(int i = NUM_DIGITS - 1; i >= 0; i--){  

        arraySum[i] = array1[i] + array2[i];
        if(carryFlag){
            arraySum[i] += carry;
            carryFlag = false;
        }

        //if on the last iteration/element of the array,
        //arraySum[0], carryFlag = false; and continue;

        if(arraySum[i] > 9){ 
            arraySum[i] = arraySum[i] - 10;
            carryFlag = true;
        }                           
    }    

Sorry if my question sounds rather vague.. But if there's a way around to making it act like a boolean: if(arraySum[0]) carryFlag = false

Answer 1

I would suggest eliminating the flag and setting different values for carry :

int carry = 0;
int arraySum[] = new int[NUM_DIGITS];
for(int i = NUM_DIGITS - 1; i >= 0; i--){  
    arraySum[i] = array1[i] + array2[i] + carry;

    // check for carry
    if(arraySum[i] > 9){ 
        arraySum[i] -= 10;
        carry = 1;
    } else {
        carry = 0;
    }
}

After the loop exits, if carry is not 0, then the summation overflowed.

Answer 2

It seems like in this implementation, you can test the value of i ?

Something like if (i==NUM_DIGITS) carryFlag = false; ?