
238 S.E.2d 299 (1977)
293 N.C. 570
STATE of North Carolina
v.
Elmer LEE.
No. 60.
Supreme Court of North Carolina.
November 11, 1977.
*302 Atty. Gen. Rufus L. Edmisten by Special Deputy Atty. Gen. Robert P. Gruber, Raleigh, for the State.
Strickland & Fuller by Robert E. Fuller, Jr., Goldsboro, for defendant.
COPELAND, Justice.
Defendant, seeking a new trial, assigns a number of errors. For reasons hereinafter indicated, we conclude that he has had a fair trial, free of prejudicial error.
Defendant first argues that it was error to deny his motion for continuance made the first day of trial. Ordinarily a motion for continuance is addressed to the sound discretion of the trial judge; however, when such a motion is based on a constitutionally guaranteed right, the question presented is one of law and not discretion and is reviewable on appeal. State v. Smathers, 287 N.C. 226, 214 S.E.2d 112 (1975).
It is defendant's contention that the court's denial of his motion for continuance prevented him from presenting an alibi witness, who was ill in Washington, D.C. and could not attend the trial. Since the right to confront one's accusers and witnesses with other testimony is guaranteed by our Federal and State Constitutions, the question here is one of law, rather than discretion. State v. Brower, 289 N.C. 644, 224 S.E.2d 551 (1976).
Denial of a motion for continuance is grounds for a new trial only upon a showing that the denial was erroneous and that defendant was prejudiced thereby. State v. Robinson, 283 N.C. 71, 194 S.E.2d 811 (1973). In the instant case, no affidavits were filed to support the motion, nor was there a written certificate from a physician attesting to the nature and existence of the proposed witness' illness. Further, defendant failed to avail himself of the procedures under G.S. 15A-813 for obtaining out-of-state witnesses. Ordinarily the absence of a witness who could have been served with a subpoena does not constitute grounds for continuance. State v. Smathers, supra. In addition, a defendant shows no prejudice where, as here, the State admits that a prospective witness, if present, would have testified as contended by the accused. State v. Utley, 223 N.C. 39, 25 S.E.2d 195 (1943); State v. Wellmon, 222 N.C. 215, 22 S.E.2d 437 (1942). This assignment of error is overruled.
Next defendant challenges the admissibility of the victim's in-court identification of defendant, as well as that of the convenience store operator. He asserts that the pre-trial photographic identification procedures carried out by the police were so suggestive in nature that the subsequent in-court identifications were irreparably tainted.
In-court identification of a defendant by a witness is barred when photographic identification procedures are "so impermissibly suggestive as to give rise to a very substantial likelihood of irreparable misidentification." Simmons v. United States, 390 U.S. 377, 384, 88 S.Ct. 967, 971, 19 L.Ed.2d 1247, 1253 (1968). "[T]he factors to be considered in evaluating the likelihood of misidentification include the opportunity of the witness to view the criminal at the time of the crime, the witness' degree of attention, the accuracy of the witness' prior description of the criminal, the level of certainty demonstrated by the witness at the confrontation, and the length of time between the crime and the confrontation." Neil v. Biggers, 409 U.S. 188, 199, 93 S.Ct. 375, 382, 34 L.Ed.2d 401, 411 (1972).
The trial judge found as fact that the victim: (1) viewed his assailant nine times for a total of about thirty seconds in the light from the station and the dome light of the car; (2) concentrated on this person's face at the time and looked at him for the purpose of identifying him; (3) was positive in his belief in the accuracy of his identification; and (4) earlier described the irregularity in his assailant's teeth later seen at trial. We further note that the photographic identification took place only six days after the crime. As to the identification *303 by the convenience store operator, the court found that the witness: (1) viewed his attacker for about four to five minutes in the well-lighted store; (2) was alert and watched the person closely; (3) chose defendant's picture after study of those shown him; and (4) had seen defendant on prior occasions. The record also discloses that this identification occurred the day after the witness was shot. These findings of fact by the trial judge are supported by competent evidence in the record and therefore are conclusive. State v. Taylor, 280 N.C. 273, 185 S.E.2d 677 (1972). In turn, the findings of fact support the court's conclusion of law that these in-court identifications were untainted by impermissible pretrial identification procedures; therefore, this assignment is without merit.
Defendant's third contention involves the admission of testimony of the convenience store operator concerning the earlier robbery of the Fast Fare store, with which defendant was not charged here. It is defendant's argument that the general rule excluding evidence of the commission of other offenses by the accused applies here.
"Evidence of other offenses is inadmissible on the issue of guilt of its only relevancy is to show the character of the accused or his disposition to commit an offense of the nature of the one charged; but if it tends to prove any other relevant fact it will not be excluded merely because it also shows him to have been guilty of an independent crime." 1 Stansbury's N.C. Evidence, (Brandis Rev. 1973), § 91, p. 289-90 (emphasis added). Assuming arguendo that the admission of this testimony was error, it was clearly cured when defendant offered alibi evidence. At this point, the fact that defendant had committed another robbery in Goldsboro, less than twenty-four hours earlier, became highly relevant and competent to disprove his alibi testimony that he had been in Washington, D.C. from 27 December to 15 January. This assignment likewise is without merit.
Defendant next argues that the trial court erred in permitting the victim to draw a diagram on a blackboard to illustrate his testimony while sitting in a wheelchair. Evidence disclosed that the victim apparently had been crippled for life after being shot in the back. Defendant asserts that the only real purpose of the demonstration was to illustrate the victim's paralysis to the jury.
This assignment clearly is without merit. It is certainly permissible for a witness to use a blackboard sketch to illustrate his testimony. State v. Cox, 271 N.C. 579, 157 S.E.2d 142 (1967). Since the evidence sought was relevant, it will not be excluded merely because it might tend to excite the jury. State v. Kirby, 273 N.C. 306, 160 S.E.2d 24 (1968).
Finally, defendant maintains that the trial court should have declared a mistrial when the State, in closing argument, exhibited photographs to the jury used to identify defendant which had been introduced on voir dire but not placed in evidence at trial. Upon having it called to his attention, the trial judge promptly instructed the jury to disregard any reference to the pictures, since none were in evidence. Ordinarily, improper argument of counsel is cured when the trial court promptly sustains the objection and cautions the jury not to consider it. State v. Covington, 290 N.C. 313, 226 S.E.2d 629 (1976); State v. Sparrow, 276 N.C. 499, 173 S.E.2d 897 (1970). Thus, this assignment is overruled.
Having examined all the assignments of error, we conclude that defendant has had a fair trial, free of error; therefore, in the verdicts and judgments we find
NO ERROR.
