I have a question about the C language queue. (enqueue

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAX_SIZE 100
#define DataType char
typedef struct ArrayQueue {
    int front;
    int rear;
    DataType queue[MAX_SIZE];
} } ArrayQueue;

void init_queue(ArrayQueue *AQ){ // Queue initialization 
    AQ->front = AQ->rear = 0;
}

intis_queue_full(ArrayQueue *AQ){ // Determine if the queue is saturated 
    return ((AQ->rear + 1) % MAX_SIZE) == AQ->front;
}

intis_queue_empty(ArrayQueue *AQ){ // Determine if the queue is blank 
    return AQ->front == AQ->rear;
} 

void queue (ArrayQueue *AQ, DataType data) { // Insert into queue 
    if (is_queue_full(AQ)){
        printf("Insertable\n");
        exit(1);
    }
    else {
        int len = strlen(data);
        AQ->rear = (AQ->rear + len) % MAX_SIZE;
        AQ->queue[AQ->rear] = data;
    }
}

void print_queue(ArrayQueue *AQ){ // Output queue items
    printf("front->");
    int i;
    for(i = AQ->front; i != AQ->rear; ){
        i = (i+1) % MAX_SIZE;
        printf("%d ", AQ->queue[i]);
    }
    printf("\n");
}

main(){
    ArrayQueue male, female;
    init_queue(&male);
    init_queue(&female);
    char name[MAX_SIZE];
    char gender;
    printf ("Customer Name: ");
    scanf("%s", name);
    printf("Please enter a star (form):"); 
    scanf(" %c", &gender);
    if(strcmp(gender, 'm'))
        enqueue(&male, name);
    else if(strcmp(gender, 'f'))
        enqueue(&female, name);

    print_queue(&male); 
}

intlen = strlen(data);
AQ->rear = (AQ->rear + len) % MAX_SIZE;
AQ->queue[AQ->rear] = data;

AQ->rear= (AQ->rear+1)% MAX_SIZE;
AQ->queue[AQ->rear] = data;