how to count the ipv4 tcp and udp using npcap in c++?

Question

I tried to code to give the statistics of a saved .pcap file in C++ using the npcap library.

My IPv4 count is correct and matches Wireshark's IPv4 count, but my TCP and UDP don't match with Wireshark's statistics.

Output of my code:

Output of the same .pcap file in Wireshark:

Here is my code:

void PcapSolutionFast::generateStats() {
    ipv4_header* ip4;
    ethernet_header* ethernet; /* The ethernet header */
    u_short eth_type;
 
    while (pcap_next_ex(pcap, &header, &data) >= 0) {
        //count every packets
        
        ethernet = (ethernet_header*)(data);
        eth_type = ntohs(ethernet->ether_type);

        if (eth_type == 0x0800) {
            

            ip4 = (ipv4_header*)(data + 14); // 14 is header length of ethernet
            if (ip4->proto == 6 /* tcp protocol number */) {
               tcpCount++;
            }
            else if (ip4->proto == 17) {//udp protocol number
                udpCount++; 
            }
            
            ipv4Count++; //count total ipv4 packets
        }
       
        ++packetCount; //count all the packets
    }

These are the data structure used:

#define ETHER_ADDR_LEN  6 //mac address length is 6
#define ETHER_HEADER_LEN 14 //header length of ethernet is fixed i.e 14
/* Ethernet or MAC addresses are 6 bytes */


/* Ethernet header */
struct ethernet_header {
    u_char ether_dhost[ETHER_ADDR_LEN]; /* Destination Mac address */
    u_char ether_shost[ETHER_ADDR_LEN]; /* Source Mac address */
    u_short ether_type; /* IP/ ARP/ RARP/ etc */
};

//divided each ip_address octet into 4 u_char
typedef struct ip_address {
    u_char byte1;
    u_char byte2;
    u_char byte3;
    u_char byte4;
}ip_address;


//ipv4 ip header
typedef struct ipv4_header {
    u_char  ver_ihl;        // Version (4 bits) + Internet header length (4 bits)
    u_char  tos;            // Type of service 
    u_short tlen;           // Total length 
    u_short identification; // Identification
    u_short flags_fo;       // Flags (3 bits) + Fragment offset (13 bits)
    u_char  ttl;            // Time to live
    u_char  proto;          // Protocol
    u_short crc;            // Header checksum
    ip_address  saddr;      // Source address
    ip_address  daddr;      // Destination address
    u_int   op_pad;         // Option + Padding
}ipv4_header;

/* IPv6 header */
typedef struct ipv6_header
{
    unsigned int
        version : 4,
        traffic_class : 8,
        flow_label : 20;
    uint16_t length;
    uint8_t  next_header;
    uint8_t  hop_limit;
    struct in6_addr saddr;
    struct in6_addr daddr;
} ipv6_header;

Why is it that my TCP and UDP counts are not the same as Wireshark's statistics?