Question

我试图在C编程中实现一个简单的队列。但我遇到了以下错误。任何人都可以找到我的程序中的错误

#include<stdio.h>
#include<stdlib.h>
#define QUENE_SIZE 10
struct queue_structure{
  unsigned int queue_front, queue_rear;
  int queue_array[10];
};
void enqueue(struct queue_structure *,int value);
int dequeue(struct queue_structure *);
int queue_full(struct queue_structure *);
int queue_empty(struct queue_structure *);
int main(){
  struct queue_structure *queue_pointer = malloc(sizeof(struct queue_structure));
  int option,number,i,dequeue_number;
  queue_pointer->queue_front = queue_pointer->queue_rear = -1;
  while(1){
    printf("Enter the option:\n");
    scanf("%d",&option);
    switch(option){
      case 1:
        printf("Enter the number to be enqueued:\n");
        scanf("%d",&number);
        if(queue_full(queue_pointer) != 1){
          enqueue(queue_pointer,number);
        }
        else{
          printf("The queue is full");
        }
        break;
      case 2:
        if(queue_empty(queue_pointer) != 1){
          dequeue_number = dequeue(queue_pointer);
          printf("%d has been dequeued",dequeue_number);
        }
        else{
          printf("Your queue is empty\n");
        }
        break;
      case 3:
        for(i = 0; i < 10 ; i++ ){
          printf("%d",queue_pointer->queue_array[i]);
        }
        break;
      case 4:
        exit(0);
        break;
    }
  }  

}
void enqueue(struct queue_structure *qs, int number){   
  if(qs -> queue_front == qs -> queue_rear){
    qs->queue_front = qs->queue_rear = -1;
  }
  else{
    (qs -> queue_rear)++;
    qs->queue_array[qs->queue_rear] = number;    
  }  
}
int dequeue(struct queue_structure *qs){
  int i;
  if(qs->queue_front == qs->queue_rear){
    qs->queue_front = qs->queue_rear = -1; 
  }
  else{
    for(i = qs->queue_front; i < qs->queue_rear ; i++){
      qs->queue_array[i] = qs->queue_array[i + 1];
    }
  }
}
int queue_full(struct queue_structure *qs){
  if((qs->queue_rear == 10) && (qs->queue_front == 0)){
    return 1;
  }
  else{
    return 0;
  }
int queue_empty(struct queue_structure *qs){
  if((qs->queue_rear && qs->queue_front) == -1){
    return 1;
  }
  else{
    return 0;
  }
}

}

我收到以下错误

/tmp/ccLJHnMG.o：在函数main': queue1.c:(.text+0xda): undefined reference to queue_empty中 collect2：ld返回1退出状态**

Answer 1

int queue_full(struct queue_structure *qs){
  if((qs->queue_rear == 10) && (qs->queue_front == 0)){
    return 1;
  }
  else{
    return 0;
  }
} <<<<<<<<<<<<<<<<<<<<<<
int queue_empty(struct queue_structure *qs){
...

Answer 2

最后的花括号是错位的，它应该是这样的：

int queue_full(struct queue_structure *qs){
  if((qs->queue_rear == 10) && (qs->queue_front == 0)){
    return 1;
  }
  else{
    return 0;
  }
} /* added the }*/

int queue_empty(struct queue_structure *qs){
  if((qs->queue_rear && qs->queue_front) == -1){
    return 1;
  }
  else{
    return 0;
  }
}
/* there was a } here that I've removed */

其他queue_empty在queue_full内定义。这不是标准C，但它似乎被gcc作为扩展支持，因此在编译期间没有错误。

使用-pedantic编译代码时，gcc会对其进行标记：

aix@aix:~$ gcc -pedantic qq.c
qq.c: In function ‘queue_full’:
qq.c:78: warning: ISO C forbids nested functions
qq.c:78: warning: ISO C90 forbids mixed declarations and code

在C中实现简单队列数据结构

2 个答案: