public String generateOperation (intleft, intright, charoperator) {
        int value=0;
        if (0<=left && left<=100 && 0<=right && right<=100) {
            if (operator == '+'){
                value = left + right;
                if ( value <= 100){
                   return ""+left+operator+right+"="+value;
                } else {
                   return "Error_1";
                }
            } else if (operator == '-'){
                value = left - right;
                if (value >= 0 ){
                   return ""+left+operator+right+"="+value;
                } else {
                   return "Error_2";
                }
            } else {
                return "Error_3";
            }
        } else {
            return "Error_4";
        }
    }
按照软件测试技术，程序共有几个简单条件？请填写正确阿拉伯数。