[1] By his first assignment of error defendant contends that the trial court erred in admitting opinion evidence that prints from *680his shoes were found in several areas of the Gold Hill Grocery for the reason that the evidence was elicited from a nonexpert witness. This assignment is without merit.
At trial, Deputy Sheriff Warren testified over objection that he observed several distinctive shoe prints in several aisles of decedent’s store. State’s exhibit number seven was identified by Officer Warren as a pair of shoes belonging to defendant, the shoes having been identified by defendant during his interrogation. He further testified that during the course of investigating the attempted robbery and the murder of Mr. Williamson, he observed a number of shoe prints in aisles in the store which had the impression of a “swiggly-type sole”; and that the impressions he observed in the store aisles were similar to those found on the soles of defendant’s pullover shoes. At no time during his testimony was Deputy Warren qualified as an expert in the identification of shoe prints.
“Tangible traces of various sorts may indicate the presence of a person or the happening of an event of a certain character at a particular place, and evidence of them is therefore admissible if the inference sought is a reasonable one.” 1 Stansbury’s North Carolina Evidence § 85 at p. 263 (Brandis Rev. 1973). Evidence of shoe prints has no logical tendency to identify a defendant as the perpetrator of a crime unless a three-pronged inference is established: (1) The shoe prints were found at or near the scene of a crime; (2) the shoe prints were made at the time of the crime; and (3) the shoe prints correspond to the shoes worn by the accused at the time of the crime. State v. Pinyatello, 272 N.C. 312, 158 S.E. 2d 596 (1968); State v. Palmer, 230 N.C. 205, 52 S.E. 2d 908 (1949). It is not necessary that a witness be qualified as an expert to entitle him to testify as to the identification of shoe prints and their correspondence with the shoes worn by a defendant. State v. Morris, 84 N.C. 756 (1881); State v. Reitz, 83 N.C. 634 (1880). See also State v. Pinyatello, supra; 2 Jones on Evidence § 14:45 (6th ed. 1972); 1 Stansbury’s North Carolina Evidence § 129 (Brandis Rev. 1973); Wharton’s Criminal Evidence §§ 193, 610 (13th ed. 1972). The bare opinion of a witness as to the identity of shoe prints is incompetent as evidence. However, when a witness is able to explain the basis upon which he draws his conclusion, such an opinion is admissible and the weight that is to be *681accorded to it is a matter for the jury to decide. State v. Pinyatello, supra; State v. Palmer, supra; State v. Reitz, supra.
As we observed above there is no requirement in our cases that a witness must be qualified as an expert before he may state an opinion as to the identification of shoe prints. It remains necessary for us to determine whether the three prerequisites of admissibility which were enunciated in State v. Palmer, supra, have been satisfied. We hold that they have been met satisfactorily. It is apparent that the shoe prints were found at or near the scene of the crime in that a number of witnesses, including Officer Warren, testified that there were bloody shoe prints throughout the Gold Hill Grocery. Evidence that indicates that a baseball bat covered with blood was found on the floor near the counter in the store tends to show that the tracks were made at the time of the commission of the crime. This inference is strengthened by defendant’s statement to the authorities that when he ran into the store, he saw his companion, Tommy Boyd, struggling with a bleeding man. Defendant said that he saw the baseball bat between the two men. Evidence which indicates that defendant and his companion, Boyd, changed clothes and left their bloody garments in the woods near Highway 58, as well as defendant’s own identification of the shoes recovered from near the highway, tends to establish that they were worn by defendant at the time of the crime.
[2] By his second assignment of error, defendant contends that the trial court erred in denying his motion for nonsuit (now denominated a motion to dismiss under G.S. § 15A-1227) for the reason that the state failed to establish a causal relationship between the assault perpetrated by the co-defendant and the death of Mr. Williamson. In a related argument, defendant contends that the trial judge failed to adequately instruct the jury with respect to the requisite causal connection between the perpetrated assault and the death of decedent. Neither contention is meritorious.
During the state’s case-in-chief, Dr. Page Hudson, Chief Medical Examiner of the State of North Carolina, detailed the nature and extent of injuries suffered by Mr. Williamson which he observed in the course of an autopsy which he conducted on deceased’s body. In addition to direct indications of both internal *682and external injuries resulting directly from blows inflicted during the course of the attempted robbery, Dr. Hudson’s internal examination of decedent’s body revealed severe ateriosclerosis in the heart and the arteries of the heart as well as scar tissue in the heart muscle itself indicating that decedent had suffered a prior heart attack. Dr. Hudson observed that the injuries which decedent incurred would have stimulated the heart enormously, providing a great deal of stress to the heart and his blood pressure level. Dr. Hudson testified that he was of the opinion that the injuries and the stress which they brought about contributed to and in fact accelerated Mr. Williamson’s death. On cross-examination, the doctor testified that “[I] would say that this man’s heart was in terrible condition. ... In part this man died from a heart attack .... Based upon my autopsy this man was a walking bombshell. Any severe stress could have caused his heart to stop .... His heart condition was such that he would have been susceptible to have his heart stop ... if his heart was bothered, stimulated or irritated.”
[3] A person is criminally responsible for a homicide only if his act caused or directly contributed to the death of the victim. State v. Jones, 290 N.C. 292, 225 S.E. 2d 549 (1976); State v. Luther, 285 N.C. 570, 206 S.E. 2d 238 (1974); State v. Horner, 248 N.C. 342, 103 S.E. 2d 694 (1958). The consequences of an assault which is the direct cause of the death of another are not excused nor is the criminal responsibility for the death lessened by a preexisting physical condition which made the victim unable to withstand the shock of the assault and without which preexisting condition the blow would not have been fatal. State v. Luther, supra; State v. Knight, 247 N.C. 754, 102 S.E. 2d 259 (1958); see generally W. LaFave & A. Scott, Handbook on Criminal Law § 35 (1972); 2 Wharton’s Criminal Law § 115 (14th ed. 1979). The testimony of Dr. Hudson, coupled with the testimony of decedent’s wife which outlined her husband’s history of high blood pressure, was sufficient for the state’s case to withstand defendant’s motion for nonsuit.
The second question presented by this assignment of error concerns the instructions of the trial court to the jury. The presiding judge instructed the jury that if they were to find defendant guilty of first-degree murder in the perpetration of a *683felony, the state must have proven beyond a reasonable doubt, inter alia,
. . . that the beating was a proximate cause of Wilbur Faulk Williamson’s death. A proximate cause is a real cause without which Wilbur Faulk Williamson’s death would not have occurred.
The defendant’s act need not have been the only cause or the last or nearest cause. It is sufficient if it concurred with some other cause, acting at the time which in combination with it, caused the death of Wilbur Faulk Williamson.
In light of our discussion of the law above, this charge was sufficient.
[4] By his third assignment of error, defendant contends that the trial court erred in admitting over objection evidence which tended to show that the decedent was accustomed to keeping large sums of money on his person. This contention is without merit.
Decedent’s wife testified that he was usually in possession of large sums of money, carrying it in his wallet and in a money clip; that he kept “several hundred dollars in his billfold” to cash checks and make change; and that he never carried less than a thousand dollars in his money clip which he used for “personal reasons.”
Relevant evidence will not be excluded simply because it may tend to prejudice the opponent or excite sympathy for the party who offers it. State v. Braxton, 294 N.C. 446, 242 S.E. 2d 769 (1978); State v. Lee, 293 N.C. 570, 238 S.E. 2d 299 (1977). However, if the only effect of the evidence is to excite prejudice or sympathy, its admission may be grounds for a new trial. State v. Lynch, 279 N.C. 1, 181 S.E. 2d 561 (1971); State v. Johnson, 270 N.C. 215, 154 S.E. 2d 48 (1967). Ordinarily, however, the reception of irrelevant evidence is considered harmless error. See generally 1 Stansbury’s North Carolina Evidence § 9 (Brandis Rev. 1973). The burden is on the party who asserts that evidence was improperly admitted to show not only error but also to show that he was prejudiced by its admission. State v. Agnew, 294 N.C. 382, 241 S.E. 2d 684 (1978); State v. Cross, 284 N.C. 174, 200 S.E. 2d 27 (1973).
While we are unable to perceive any grounds upon which the testimony in question was relevant to the issues in the case *684against defendant, defendant has not carried his burden of showing that the evidence was so prejudicial that had it not been for the admisison of the irrelevant evidence a different result would have ensued. See State v. Cross, supra. Furthermore, earlier in the trial, Officer Charles E. Ward, a detective with the Halifax County Sheriff’s Department, was permitted to testify without objection that in the course of his investigation of the crimes he had the occasion to examine the clothing of the decedent; and that Mr. Williamson was carrying on his person at the time of the attempted robbery the sum of $1,630 in his billfold and his money clip. While the testimony of Mrs. Williamson on this point was irrelevant because there was no other evidence which suggested that defendant and Boyd knew of decedent’s practice, testimony of a similar nature had already been elicited from Detective Ward and had been placed before the jury for its consideration.
By his fourth assignment of error, defendant contends that the trial court committed error by failing to adequately state the contentions of defendant and by failing to instruct the jury on lesser included offenses which were raised by the evidence. Neither contention is meritorious.
Defendant asserts that in submitting the case to the jury, the trial judge failed to address his contention that the decedent died not from the perpetrated assault but from a preexisting heart condition. He further argues that the judge failed to state any of his contentions regarding the relationship between the assault perpetrated upon the victim and the ultimate cause of his death. Defendant misconstrues the judge’s charge. At no point did the judge attempt to summarize the contentions of either the state or of the defendant. In fact, he pointed out his failure to do so to the jury, instructing them that it was their “ . . . duty to not only consider all of the evidence, but also to consider all of the arguments, the contentions and positions urged by the state’s District Attorney and the defendant’s attorney in their speeches . . . and any other contentions that arise from the evidence . . . .” The trial judge is not required to state the contentions of litigants. State v. Hewett, 295 N.C. 640, 247 S.E. 2d 886 (1978); State v. Dietz, 289 N.C. 488, 223 S.E. 2d 357 (1976).
[5] In submitting the case to the jury, the trial judge submitted two possible verdicts as to each charge which defendant faced. *685The jury was given the option of finding defendant guilty of attempted armed robbery with a dangerous weapon or not guilty of that charge; and guilty of first-degree murder or not guilty of that charge. Defendant argues that the evidence in the light most favorable to him could have permitted the jury to conclude that his role in the case was that of an accessory after the fact of robbery with a dangerous weapon.
There is no error in a failure to instruct a jury on the crime of being an accessory after the fact where all of the evidence construed together tends to show actual participation in the substantive crime charged. State v. Brower, 289 N.C. 644, 224 S.E. 2d 551 (1976). An accessory after the fact is an individual who, after a felony has been committed, with knowledge of its commission, renders personal assistance to the felon in any manner to aid him to escape arrest or punishment. State v. Potter, 221 N.C. 153, 19 S.E. 2d 257 (1942); State v. Dunn, 208 N.C. 333, 180 S.E. 708 (1935). There is nothing in the record of this case which indicates that there was any evidence upon which the jury could conclude that defendant was an accessory after the fact. His own testimony indicates that Boyd informed him of the planned robbery and instructed him as to what he was to do. Defendant complied with those instructions. By his own statements, therefore, defendant acknowledged that he aided in the actual perpetration of the crime.
[6] By his sixth assignment of error, defendant contends that the trial court erred in sentencing him to life imprisonment, alleging cruel and unusual punishment and a denial of the equal protection of the laws in light of the subsequent imposition upon his codefendant of a sentence of sixty to eighty years imprisonment. This contention is without merit.
The trial court, upon conviction of defendant on both the attempted armed robbery charge and the murder charge, conducted a sentencing hearing for the determination of defendant’s punishment for the capital felony of first-degree murder. At the close of the proceeding, the jury recommended that defendant be sentenced to life imprisonment on the murder conviction. Defendant had been previously sentenced to life on the attempted armed robbery charge. At a subsequent session of the court the code-fendant, Thomas Boyd, was permitted to plead guilty to second-*686degree murder and he was sentenced to a term of sixty to eighty years in prison.
If the recommendation of the jury in the sentencing phase of a capital case is that the defendant be imprisoned for life, the trial judge is obligated to impose that sentence. G.S. § 15A-2002. In that instance, he has no discretion to exercise in the imposition of sentence. Punishment which does not exceed the limits fixed by statute cannot be classified as cruel and unusual punishment in the constitutional sense unless the punishment provisions of the statute itself are unconstitutional. State v. Williams, 295 N.C. 655, 249 S.E. 2d 709 (1978); State v. Cradle, 281 N.C. 198, 188 S.E. 2d 296, cert. denied 409 U.S. 1047, 34 L.Ed. 2d 499, 93 S.Ct. 537 (1972). Life imprisonment for first-degree murder does not constitute cruel and unusual punishment. Compare, Gregg v. Georgia, 428 U.S. 153, 49 L.Ed. 2d 859, 96 S.Ct. 2909 (1976); State v. Barfield, 298 N.C. 306, 259 S.E. 2d 510 (1979). A mere disparity in the sentences imposed upon codefendants is not sufficient to amount to cruel and unusual punishment in the constitutional sense. State v. Benton, 276 N.C. 641, 174 S.E. 2d 793 (1970).
[7] By his fifth assignment of error, defendant contends that the trial court erred in failing to arrest judgment entered on the conviction of attempted armed robbery; he argues that it merged into the first-degree murder charge because the state proceeded on the theory of felony murder. The state concedes error on this point. We agree.
The indictment which charged defendant with the first-degree murder of Wilbur Faulk Williamson alleged that he “feloniously, wilfully, and of his malice aforethought, deliberately and premeditately did kill and murder” decedent. The state proceeded at trial on the theory of felony murder. The case was submitted to the jury after a charge on the elements of felony murder which included a requirement that the state prove beyond a reasonable doubt that the defendant attempted to commit robbery.
That there is such a variance is not fatal to the conviction. Notwithstanding the allegation contained in the indictment pertaining to a killing with malice after premeditation and deliberation, a conviction of first-degree murder will be sustained if the evidence shows and the jury finds that the killing was done in the *687perpetration of or in the attempt to perpetrate a felony. State v. Moore, 284 N.C. 485, 202 S.E. 2d 169 (1974). A defendant who is convicted of first-degree murder on the theory of felony murder cannot be subjected to additional punishment for the underlying felony as an independent criminal offense. State v. Small, 293 N.C. 646, 239 S.E. 2d 429 (1977); State v. McLaughlin, 286 N.C. 597, 213 S.E. 2d 238 (1975), death sentence vacated, 428 U.S. 903, 49 L.Ed. 2d 1208, 96 S.Ct. 3206 (1976); State v. Moore, supra. Accordingly, the judgment imposed on the verdict finding defendant guilty of attempted armed robbery with a dangerous weapon is arrested.
In defendant’s trial and the judgment entered for first-degree murder, we find no error.
In the armed robbery case, the judgment is arrested.