/* http://www.mitbbs.com/article_t1/JobHunting/32364859_0_1.html * */ import java.io.*; import java.util.*; public class ValidExpression { public static void main(String[] args) { String expr = "1+2"; solve(expr); } public static void solve(String expr) { } public boolean isDigit(char c) { return c>='0' && c<='9'; } public boolean isOperator(char c) { return c=='+' || c=='-'; } }