The mere fact that one’s proposed lawful use of his own land will diminish the value of adjoining or nearby lands of another does not give to such other person a standing to maintain an action, or other legal proceeding, to prevent such use. Harrington & Co. v. Renner, 236 N.C. 321, 72 S.E. 2d 838; 1 Am. Jur. 2d, Adjoining Landowners, § 2. If, however, the proposed use is unlawful, as where it is prohibited by a valid zoning ordinance, the owner of adjoining or nearby lands, who will sustain special damage from the proposed use through a reduction in the value of his own property, does have a standing to maintain such proceeding. Zopfi v. City of Wilmington, 273 N.C. 430, 160 S.E. 2d 325; Harrington & Co. v. Renner, supra.
[2, 3] The courts, at the suit of a landowner so threatened with injury, may not compel a city or other governmental unit to exercise a zoning authority conferred upon it by statute, or prevent it from amending or repealing a valid zoning ordinance previously adopted by it. Zopfi v. City of Wilmington, supra; In Re Markham, 259 N.C. 566, 131 S.E. 2d 329; McKinney v. High Point, 239 N.C. 232, 79 S.E. 2d 730. If, however, that which purports to be an amendment permitting a use of property forbidden by the original ordinance is, itself, invalid, the prohibition upon the use remains in effect. In that event, the owner of other land, who will be specially damaged by such proposed use, has standing to maintain a proceeding in the courts to prevent it. Seer Zopfi v. City of Wilmington, supra; Crozier v. County Commissioners of Prince George’s County, 202 Md. 501, 97 A. 2d 296, 37 A.L.R. 2d 1137; Annot., 37 A.L.R. 2d 1143.
[4, 5] Similarly, the order of a board of adjustment purporting *162to grant an exception to a valid zoning ordinance, which order is in excess of the authority of such board, leaves the proposed use within the prohibition of the ordinance and, therefore, unlawful. Thus, the appellants are proper parties ■ to attack in this proceeding the ■ validity of the order of the Board of Adjustment. Their contention is that the county zoning ordinance forbids the proposed use of the Jones land without a properly granted exception and the Board of Adjustment has no authority to grant the exception.
. Counties have no inherent authority to enact zoning ordinances. In Harrington & Co. v. Renner, supra, this Court conceded, for the purpose of the question then before it, that the General Assembly may, under the Constitution of North Carolina, empower a county board of commissioners to enact ordinances providing for zoning districts in the rural areas of the county, but expressly stated it did not decide that question since, at that time, the General Assembly had not undertaken to do so. Subsequently, the General Assembly enacted Article 20B, Ch. 153,- of the General Statutes, which expressly confers such power upon the boards of county commissioners. County ordinances, adopted pursuant to this Act of the General Assembly, have been treated as valid legislative enactments in at least three decisions of this Court, in none of which was the authority of the General Assembly to delegate the power questioned. Michael v. Guilford County, 269 N.C. 515, 153 S.E. 2d 106; Austin v. Brunnemer, 266 N.C. 697, 147 S.E. 2d 182; Durham County v. Addison, 262 N.C. 280, 136 S.E. 2d 600.
[7, 8] In Harrington & Co. v. Renner, supra, this Court recognized that “the General Assembly may delegate power to a municipal corporation to enact zoning ordinances in the exercise of police power of the State,” and innumerable decisions of this Court have recognized such power in cities and towns by virtue of G.S. 160-172, et seq. The authority of the General. Assembly to delegate to municipal corporations power to legislate concerning local problems, such as zoning, is an exception (established by custom in most, if not all, of the states) to the general rule that legislative powers, vested in the General Assembly by Art. II, § 1, of the Constitution of North Carolina, may not be delegated by it. 16 Am. Jur. 2d, Constitutional Law, §§ 250, 251. This Court has held that this exception to the doctrine of non-delegation is not limited to a delegation of such legislative authority to incorporated cities and towns, but extends, as to other types of local matters, to a like delegation to counties and other units established by the General Assembly for local government. Efird v. Comrs. of Forsyth, 219 N.C. 96, 12 S.E. 2d 889; Tyrrell County v. Holloway, 182 N.C. 64, 108 S.E. 337; *163 Smith v. School Trustees, 141 N.C. 143, 53 S.E. 524. See also, State v. Smith, 265 N.C. 173, 143 S.E. 2d 293. We perceive no basis for a distinction in this respect between municipal corporations and counties. We, therefore, hold that the General Assembly may, notwithstanding Art. II, § 1, of the Constitution of North Carolina, confer upon county boards of commissioners power to adopt zoning ordinances otherwise valid.
G.S. 153-266.10, “for the purpose of promoting health, safety, morals, or the general welfare,” confers upon the board of county commissioners of any county the power “to regulate and restrict * * * the location and use of buildings, structures, and land for trade, industry, residence or other purposes, except farming.” It further provides:
“Such regulations may provide that a board of adjustment may determine and vary their application in harmony with their general purpose and intent and in accordance with general or specific rules therein contained. Such regulations may also provide that the board of adjustment or the board of county commissioners may issue special use permits or conditional use permits in the classes of cases or situations and in accordance with the principles, conditions, safeguards, and procedures specified therein, and may impose reasonable and appropriate conditions and safeguards upon such permits.” (Emphasis added.)
G.S. 153-266.11 provides that the board of county commissioners for such purposes “may divide the county, or portions of it * * * into districts * * * and within such districts it may regulate and restrict the erection, construction, reconstruction, alteration, repair, or use of buildings, structures or land.” (Emphasis added.)
G.S. 153-266.17 provides that if the board of commissioners exercises these powers, it “shall provide for the appointment of a board of adjustment” and that “the zoning ordinance may provide that the board of adjustment may permit special exceptions to the zoning regulations in the classes of cases or situations and in accordance with the principles, conditions, safeguards, and procedures specified in the ordinance.” (Emphasis added.)
 These provisions are substantially the same as those in G.S. 160-172, et seq., conferring zoning powers upon municipal corporations. Under those statutes, this Court has held that the legislative body of the municipal corporation may not delegate to the municipal board of adjustment the power to zone; that is, the power originally vested in the General Assembly to legislate with reference to the *164use which may be made of land and the structures which may be erected or located thereon. In Re O’Neal, 243 N.C. 714, 91 S.E. 2d 189; James v. Sutton, 229 N.C. 515, 50 S.E. 2d 300. In Lee v. Board of Adjustment, 226 N.C. 107, 37 S.E. 2d 128, it is said that G.S. 160-172, et seq., confer no legislative authority upon such municipal board of adjustment and thus such board “is not left free to make any determination whatever that appeals to its sense of justice.” It follows that a county zoning ordinance may not delegate such legislative powers to the county board of adjustment.
Admittedly, the line dividing administrative powers which may be delegated from legislative powers which may not be delegated is not sharp and clearly defined. Consequently, decisions by this Court and by other courts as to its location have not been entirely harmonious. However, the governing principle, applicable to the delegation of powers by the General Assembly to State agencies, is also applicable to determine what powers may be conferred by a city or county upon its board of adjustment in a zoning ordinance. That principle has been thus stated in Coastal Highway v. Turnpike Authority, 237 N.C. 52, 74 S.E. 2d 310:
“Since legislation must often be adapted to complex conditions involving numerous details with which the Legislature cannot deal directly, the constitutional inhibition against delegating legislative authority does not deny to the Legislature the necessary flexibility of enabling it to lay down policies and establish standards, while leaving to designated governmental agencies and administrative boards the determination of facts to which the policy as declared by the Legislature shall apply.
* * -X-
“Here we pause to note the distinction generally recognized between a delegation of the power to make a law, which necessarily includes a discretion as to what it shall be, and the conferring of authority or discretion as to its execution. The first may not be done, whereas the latter, if adequate guiding standards are laid down, is permissible under certain circumstances.
* -X- *
“In short, while the Legislature may delegate the power to find facts or determine the existence or non-existence of a factual situation or condition on which the operation of a law is made to depend, or another agency of the government is to come into existence, it cannot vest in a subordinate agency the power to apply or withhold the application of the law in its *165absolute or unguided discretion. 11 Am. Jur., Constitutional Law, Sec. 234. * * * '
“[B]y the decided weight of authority, the rule is that ‘if the statute requires or authorizes the court or other agency to pass upon questions of public policy involved, * * * there is an attempted delegation of legislative power and the statute is invalid.’ 37 Am. Jur., Municipal Corporations, Sec. 8. * * *
“Manifestly, the power to determine whether the construction and operation of a toll road or toll bridge in any given instance will be ‘in the public interest’ is purely a legislative question to be resolved only in the exercise or under the direction of legislative powers of guidance and control.”
When a statute, or ordinance, provides that a type of structure may not be erected in a specified area, except that such structure may be erected therein when certain conditions exist, one has a right, under the statute or ordinance, to erect such structure upon a showing that the specified conditions do exist. The legislative body may confer upon an administrative officer, or board, the authority to determine whether the specified conditions do, in fact, exist and may require a permit from such officer, or board, to be issued when he or it so determines, as a further condition precedent to the right to erect such structure in such area. Such permit is not one for a variance or departure from the statute or ordinance, but is the recognition of a right established by the statute or ordinance itself. Consequently, the delegation to such officer, or board, of authority to make such determination as to the existence or nonexistence of the specified conditions is not a delegation of the legislative power to make law.
Delegation to an administrative officer, or board, of authority to issue or refuse a permit for the erection of a specified type of structure in a given area, dependent upon whether such officer, or board, considers such structure in such area, under prevailing conditions, conducive to or adverse to the public interest or welfare is a different matter. Such delegation makes the determinative factor the opinion of such officer, or board, as to whether such structure in such area, under prevailing conditions, would be desirable or undesirable, beneficial to the community or harmful to it. This is a delegation of the power to make a different rule of law, case by case. This power may not be conferred by the legislative body upon an administrative officer or board.
Section 3-10 of the ordinance here in question is not an enumeration of conditions which, when met, bring into operation the excep*166tion; that is, confer upon the landowner the right to establish a mobile home park upon his land. This section is a list of regulations and specifications to which the park must conform if and when the permit to establish it is issued. The last of its provisions confers upon the Board of Adjustment authority to impose further requirements. This authority is, however, expressly limited to such further requirements as may reasonably be deemed necessary to accomplish the purposes of the ordinance, which purposes are, in turn, specifically fixed and declared in the ordinance. Consequently, this authorization does not set the Board of Adjustment free to roam at large within its own concept of what is best for the public. It is not, upon its face, an unlawful delegation of legislative power. We are not presently called upon to determine the validity of any requirement imposed by the Board of Adjustment under the authority of this section.
 To ascertain the circumstances, under which the Board of Adjustment is to issue a permit to establish a mobile home park in the A-l Agricultural District, we must turn to Section 6-13B of the ordinance. There we find the board is to grant such permit “in accordance with the principles, conditions, safeguards and procedures specified in this ordinance,” or is to deny the permit “when not in harmony with the purpose and intent of this ordinance.” Thus far, it is the ordinance, not the Board of Adjustment which determines the circumstances, the existence of which calls into play the provision for the exception, the board having authority to determine only the existence or absence of those circumstances. This determination is a matter of administration, not a delegation of the legislative power to change or add to the law as fixed in the ordinance.
 Section 6-13B does not stop there, however. It goes on to provide that the Board of Adjustment shall grant no permit for the establishment in this district of a mobile home park unless the board receives a written application, conducts a public hearing after due notice and thereupon finds: (1) It is authorized, by the section of the ordinance designated in the application, to grant such permit — i.e., the circumstances specified by the ordinance itself exist; and (2) the granting of the permit “will not adversely affect the public interest” — i.e., in the opinion of the Board of Adjustment, the establishment of the proposed mobile home park will not be detrimental to the public good.
[12, 13] The Court of Appeals apparently regarded the second of these required findings as limited to a finding that the proposed mobile home park will not violate conditions specified in or con *167flict with purposes declared in the ordinance itself. We do not so construe this provision of Section 6-13B. So construed, it would be ^surplusage, a mere repetition of the first required finding. When a statute or ordinance prescribes two or more prerequisites to official action, the' presumption is that none of them is a mere repetition of .the others. “All parts of the same statute dealing with the same subject are to be construed together as a whole, and every part thereof must be given effect if this can be done by any fair and ■reasonable intendment.” Strong, North Carolina Index 2d, Statutes, § 5, and cases therein cited.
Section 7-1 of the ordinance provides that the provisions set out in the ordinance itself shall be interpreted “as the minimum requirements for the promotion of the public safety, health, convenience, prosperity, and general welfare.” This is a further indication that Section 6-13B was intended to permit the Board of Adjustment to go further than the declared objectives of the ordinance in determining what will adversely affect the “public interest.”
 G.S. 153-266.17 provides that a county zoning ordinance may authorize the county board of adjustment to “permit special exceptions to the zoning regulations in classes of cases or situations and in accordance with the principles, conditions, safeguards and procedures specified in the ordinance.” (Emphasis added.) The provision of Section 6-13B of the Guilford County ordinance, requiring the Board of Adjustment to deny the permit if it finds the granting of it will adversely affect the public interest, is in excess of the authority which this statute permits to be so conferred upon the board.
So much of Section 6-13B of this ordinance as requires the Board of Adjustment to deny a permit for the establishment of a mobile home park in the A-l Agricultural District unless it finds “that the granting of the special exception will not adversely affect the public interest” is, therefore, beyond the authority of the Board of County Commissioners to enact and so is invalid. This, however, does not invalidate the action of the board. It did not deny a permit. It granted one.
[14, 15] There is nothing in the ordinance to suggest that the Board of County Commissioners intended that the invalidity of this requirement would make impossible the establishment anywhere in Guilford County of a mobile home park. On the contrary, Section 7-2 of the ordinance expressly provides that if “any section, sentence, clause, or phrase of this Ordinance be held invalid * * * such decision shall not affect the validity of the remaining portions *168of this Ordinance.” It is well settled that if valid provisions of a statute, or ordinance, are separable from invalid provisions therein, so that if the invalid provisions be stricken the remainder can stand alone, the valid portions will be given full effect if that was the legislative intent. Fox v. Commissioners of Durham, 244 N.C. 497, 94 S.E. 2d 482; Power Co. v. Clay County, 213 N.C. 698, 197 S.E. 603. “The invalidity of one part of a statute [or ordinance] does not nullify the remainder when the parts are separable and the invalid part was not the consideration or inducement for the Legislature [or board of county commissioners] to enact the part that is valid.” Bank v. Lacy, 188 N.C. 25, 123 S.E. 475. When the statute, or ordinance, could be given effect had the invalid portion never been included, it will be given such effect if it is apparent that the legislative body, had it known of the invalidity of the one portion, would have enacted the remainder alone. Commissioners v. Boring, 175 N.C. 105, 111, 95 S.E. 43. Here, the legislative body, the Board of County Commissioners, has expressly declared in the ordinance that it would have done so. Therefore, the effect of the ordinance is to permit the Board of Adjustment to issue the permit in question without any finding as to the effect of it upon the public interest. It is interesting to note that this is precisely what the board did prior to the first order of the superior court, so there can be no question as to what the board would have done in this specific case had the ordinance not contained the invalid requirement.
It follows that the Court of Appeals was correct in affirming the judgment of the superior court which sustained the order of the Board of Adjustment granting the “special exception” permit.