Java char array to int
Is开发者_如何学C it possible to convert a char[]
array containing numbers into
an int
?
Does the char[]
contain the unicode characters making up the digits of the number? In that case simply create a String from the char[]
and use Integer.parseInt:
char[] digits = { '1', '2', '3' };
int number = Integer.parseInt(new String(digits));
Even more performance and cleaner code (and no need to allocate a new String object):
int charArrayToInt(char []data,int start,int end) throws NumberFormatException
{
int result = 0;
for (int i = start; i < end; i++)
{
int digit = (int)data[i] - (int)'0';
if ((digit < 0) || (digit > 9)) throw new NumberFormatException();
result *= 10;
result += digit;
}
return result;
}
char[] digits = { '0', '1', '2' };
int number = Integer.parseInt(String.valueOf(digits));
This also works.
It is possible to convert a char[]
array containing numbers into an int
. You can use following different implementation to convert array.
Using
Integer.parseInt
public static int charArrayToInteger(char[] array){ String arr = new String(array); int number = Integer.parseInt(arr); return number; }
Without
Integer.parseInt
public static int charArrayToInt(char[] array){ int result = 0; int length = array.length - 1; for (int i = 0; i <= length; i++) { int digit = array[i] - '0'; //we don't want to cast by using (int) result *= 10; result += digit; } return result; }
Example:
public static void main(String []args){
char[] array = {'1', '2', '3', '4', '5'};
int result = 0;
result = charArrayToInteger(array);
System.out.println("Using Integer.parseInt: " + result);
result = charArrayToInt(array);
System.out.println("Without Integer.parseInt: " + result);
}
Output:
Using Integer.parseInt: 12345
Without Integer.parseInt: 12345
Another way with more performance:
char[] digits = { '1', '2', '3' };
int result = 0;
for (int i = 0; i < chars.length; i++) {
int digit = ((int)chars[i] & 0xF);
for (int j = 0; j < chars.length-1-i; j++) {
digit *= 10;
}
result += digit;
}
Well, you can try even this
char c[] = {'1','2','3'};
int total=0,x=0,m=1;
for(int i=c.length-1;i>=0;i--)
{
x = c[i] - '0';
x = x*m;
m *= 10;
total += x;
}
System.out.println("Integer is " + total);
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