代码片段

public static void eval(){
    int b = num.pop();
    int a = num.pop();
    char c = op.pop();
    if(c == '+') num.push(a + b);
    else if(c == '-') num.push(a - b);
    else if(c == '*') num.push(a * b);
    else num.push(a / b);
}

======>>>>>>>>>>

public static void eval(){
    int b = num.pop();
    int a = num.pop();
    char c = op.pop();
    int x = 0;
    if(c == '+') x = a + b;
    else if(c == '-') x = a - b;
    else if(c == '*') x = a * b;
    else x = a / b;
    num.push(x);
}

注意代码的简洁性！！！！！