循环队列的基本操作

#include 
#include 
#define MAXSIZE 20

typedef struct{
    char data[MAXSIZE];
    int rear;
    int front;
}SeqQueue;

SeqQueue * init(){
    SeqQueue * sq;
    sq = (SeqQueue *)malloc(sizeof(SeqQueue));
    sq->rear = 0;
    sq->front = 0;
    return sq;
}

void inSeqQueue(SeqQueue * sq,char x){
    if((sq->rear+1)%MAXSIZE == sq->front){
        printf("the queue is full!\n");
    }else{
        sq->rear = (sq->rear + 1) % MAXSIZE;
        sq->data[sq->rear] = x;
    }
}

char outSeqQueue(SeqQueue * sq){
    char x;
    if(sq->rear == sq->front){
        printf("the queue is empty!\n");
        return '0';
    }else{
        sq->front = (sq->front + 1) % MAXSIZE;
        x = sq->data[sq->front];
        return x;
    }
}

void print(SeqQueue * sq){
    int i;
    i = (sq->front + 1) % MAXSIZE;
    while(i != sq->rear){
        printf("%4c",sq->data[i]);
        i = (i+1) % MAXSIZE;
    }
    printf("%4c",sq->data[i]);
    printf("\n");
}

int main(){
    SeqQueue * sq;
    char x;
    char y;
    sq = init();
    printf("please input the values of the queue!\n");
    scanf("%c",&x);
    while(x!='\n'){
        inSeqQueue(sq,x);
        scanf("%c",&x);
    }
    print(sq);
    printf("after output (once)\n");
    y = outSeqQueue(sq);
    printf("the output value is:%c\n",y);
    print(sq);
    printf("after output (twice)\n");
    y = outSeqQueue(sq);
    printf("the output value is:%c\n",y);
    print(sq);

    return 0;
}