Find the number of digits in an integer

Integer Length "For" Loop

for(long long int temp = number; temp >= 1;)
{
    temp/=10;
    decimalPlaces++;
} 

Integer Length Conversion To String

String s = new Integer(t).toString(); 
int len = s.length();

Integer Length Logarithmic Calculation

int digits = (int)(Math.log(integer) / Math.log(10) + 1);