char和int的转换

import java.util.Scanner;
public class test7 {

	public static void main(String[] args) {
		// TODO Auto-generated method stub

		Scanner in=new Scanner(System.in);
		String a=in.next();
		char b[]=a.toCharArray();
		System.out.println(chartoint(b));

	}

	public static int chartoint(char a[]) {
		int str=0;int value=0;int v=1;
		if (a==null) {
			return 0;
		}
		if ( a[0]=='-' || a[0]=='+') {
			str++;
			v=(a[0]=='-'?-1:1);
		}
		for (int i = str; i < a.length; i++) {
			if (a[i]>='0' && a[i]<='9') {

				value=value*10+a[i]-'0';
			}

		}

		return v*value;

	}

}