Incremental index doesn't change at end of for loop - arduino

Question

I want to interface Arduino with PLC to pull some information.
My problem is at Function 3: Set alarm flag / reset flag. This function is used to compare history value and present value. I tried to process some integer number (test_number) and process like binary 16 bits data for finding 1 at some bit. I found the for loop in Findbit function, which should repeat 16 times, runs infinitely. It does not change the incremental index (variable name bit_1) which is still stuck at 1.
This is my code :
int test_number_array[10] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int test_number = 0;
int bit_1 = 0;
int Andbit = 0;
const char* message;
int flagAlarm[2][16] = {};
int flagReset[2][16] = {};
void setup()
{
// put your setup code here, to run once:
Serial.begin( 9600 );
}
void loop()
{
// put your main code here, to run repeatedly:
for (int j = 1; j <= 2; j++)
{
for (int i = 1; i <= 2; i++) // Example with 2 modbus address
{
unsigned int address = 40000 + i;
Serial.print ("Modbus address = ");
Serial.println(address, DEC);
pull_data(i);
Serial.print("Test number is ");
Serial.println(test_number);
Findbit(i);
Serial.println("------------------------------------------------- ");
}
}
while (1)
{
}
}
// ---------------Function 1 : Function finding alarm bit-----------------//
void Findbit(int i)
{
for (bit_1 = 0; bit_1 <= 15; bit_1++)
{
Andbit = test_number & 1;
Serial.print("Test number (BINARY) is ");
Serial.println(test_number, BIN);
Serial.print("Check at bit number ");
Serial.println(bit_1);
Serial.print("And bit is ");
Serial.println(Andbit, BIN);
Serial.print("flagAlarm(Before1) = ");
Serial.println(flagAlarm[i][bit_1]);
Serial.print("flagreset(Before1) = ");
Serial.println(flagReset[i][bit_1]);
if (Andbit == 1) //found "1" pass into loop
{
flagAlarm[i][bit_1] = 1;
}
else
{
}
Serial.print("flagAlarm(Before2) = ");
Serial.println(flagAlarm[i][bit_1]);
Serial.print("flagreset(Before2) = ");
Serial.println(flagReset[i][bit_1]);
Set_reset_flag(i,bit_1);
test_number = test_number >> 1;
Serial.print("flagAlarm(After) = ");
Serial.println(flagAlarm[i][bit_1]);
Serial.print("flagreset(After) = ");
Serial.println(flagReset[i][bit_1]);
Serial.println(" ");
}
}
// -----------------------Function 2 : Pull data------------------------- //
int pull_data(int i)
{
i = i - 1;
test_number = test_number_array[i];
return test_number;
}
// -------------Function 3 : Set alarm flag / reset flag ---------------- //
void Set_reset_flag(int i, int bit_1)
{
Serial.print("i = ");
Serial.println(i);
Serial.print("bit_1 = ");
Serial.println(bit_1);
if (flagAlarm[i][bit_1] == 1 && flagReset[i][bit_1] == 0)
{
Serial.print("Alarm at bit ");
Serial.println(bit_1);
flagAlarm[i][bit_1] = 0;
flagReset[i][bit_1] = 1;
}
else if (flagAlarm[i][bit_1] == 0 && flagReset[i][bit_1] == 1)
{
Serial.print("Reset Alarm at bit ");
Serial.println(bit_1);
flagReset[i][bit_1] = 0;
}
else if (flagAlarm[i][bit_1] == 1 && flagReset[i][bit_1] == 1)
{
Serial.print("Alarm still active at bit ");
Serial.println(bit_1);
flagAlarm[i][bit_1] = 0;
flagReset[i][bit_1] = 1;
}
else
{
}
}

Answer 1

Could it be that your bit_1 variable is modified from some other code not mentioned here, or get optimized at all? Also, is it necessary to make a loop counter a global variable? Can you declare it inside the Findbit function?