C 程序中的 integer scanf 序列時出現總線錯誤

Question

如果 C 中以下格式的輸入為 -1，我必須采用 integer 輸入並結束 while 循環：

111 1 1
111 1 1
111 1 1
-1

我的代碼在主 function（代碼結尾）中的第 3 次 scanf 后出現總線錯誤。 我知道這是關於空白的，但我不知道要解決它。 如果它很重要，我正在使用 M1 在 MacBook 上進行測試。 順便說一句 print("break")s 僅用於測試，我不想進行任何垃圾打印或掃描。

#include <stdio.h>
#include <stdlib.h>

struct employee{
    int ID;
    int freeAt;
    int totalTime;
    struct employee *next;
};

struct customer{
    int ID;
    int startTime;
    int processTime;
    int waitingTime;
    int helper;
    struct customer *front;
    struct customer *rear;
    struct customer *next;
};

typedef struct employee employee;
typedef struct customer customer;

void new_employer(employee *top, int id){ //Insert employees by id
    employee *ptr;
    ptr = (employee*)malloc(sizeof(employee));
    ptr->ID = id;
    ptr->freeAt = 0;
    ptr->totalTime = 0;

    if (top == NULL){
        ptr->next =  NULL;
        top = ptr;
    }
    else{
        ptr->next = top;
        top = ptr;
    }
}

void help_customer(customer *c, employee *top){ //Match customer with suitable employee
    employee *ptr;
    ptr = (employee*)malloc(sizeof(employee));
    ptr = top;

    if (top==NULL){
        c->startTime = c->startTime + 1;
        c->waitingTime++;
        help_customer(c,ptr);
    }

    if(c->startTime>=top->freeAt){
        c->helper = top->ID;
        top->freeAt = c->startTime + c->processTime;
        top->totalTime = top->totalTime + c->processTime;
    }
    else{
        help_customer(c, top->next);
    }
}

void new_customer(customer *c, employee *top, int id, int start, int process){ //New customer
    customer *ptr;
    ptr = (customer*)malloc(sizeof(customer));
    ptr->ID = id;
    ptr->startTime = start;
    ptr->processTime = process;
    ptr->waitingTime = 0;
    help_customer(ptr,top);
    
    if (c->front == NULL){
        c->front = ptr;
        c->rear = ptr;
        c->next = NULL;
    }
    else{
        c->rear->next = ptr;
        c->rear = ptr;
        c->rear->next = NULL;
    }
}

void customerStats(customer *c){ //Printing customer stats at the end of the transactions
    customer *ptr;
    ptr = (customer*)malloc(sizeof(customer));
    ptr = c->front;

    if(ptr == NULL){
        printf("\nQUEUE IS EMPTY");
    }
    else{
        printf("\n");
        while (ptr!=c->rear){
            printf("%d ", ptr->ID);
            printf("%d ", ptr->helper);
            printf("%d ", ptr->startTime);
            printf("%d ", ptr->processTime);
            printf("%d\n", ptr->waitingTime);
            ptr = ptr->next;
        }

        printf("%d ", ptr->ID);
            printf("%d ", ptr->helper);
            printf("%d ", ptr->startTime);
            printf("%d ", ptr->processTime);
            printf("%d\n", ptr->waitingTime);
    }
}

void employeeStats(employee *top){ //Printing employee stats at the end of the transactions
    employee *ptr;
    ptr = (employee*)malloc(sizeof(employee));
    ptr = top;
    
    if (top==NULL){
        printf("\nSTACK IS EMPTY");
    }
    else{
        while (ptr!=NULL){
            printf("%d ", ptr->ID);
            printf("%d\n", ptr->totalTime);
            ptr = ptr->next;
        }
    }
}



int main(){
    employee *e;
    for(int i=1;i>7;i++){
        new_employer(e,i);
    }

    customer *c;
    int id;
    int start;
    int process;
    while(1){       //********I GET BUS ERROR HERE ON 3RD SCANF**************
        scanf("%d", &id);
        printf("break1");
        if (id==-1){
            break;
        }
        scanf("%d", &start);
        printf("break2");
        scanf("%d", &process);
        printf("break3");
        new_customer(c,e,id,start,process);
    }

    customerStats(c);
    employeeStats(e);
}

這是終端：

111
break11
break21
zsh: bus error  ./main

Answer 1

如果您一開始就編寫最少的代碼，並在添加更多代碼之前讓它工作，這會有所幫助。

這是一個部分更正，顯示了為什么您會出現未定義的行為（崩潰）。 閱讀每一行並了解它與您的代碼有何不同以及有何不同。 一旦理解了這一點，您就可以（謹慎地，一步一步地）一次再添加一個元素，並在朝着目標前進的過程中進行測試、測試、測試。

typedef struct employee {
    int ID;
    int freeAt;
    int totalTime;
    struct employee *next;
} employee_t;

employee_t *new_employeEEEE( employee_t *top, int id ) { //Insert employees by id
    employee_t *ptr = (employee_t*)calloc( 1, sizeof(*ptr) ); // use calloc()
    // Omitting check of calloc failing
    ptr->ID = id;

    ptr->next = top; // reverse sequence, but at least it works...

    return ptr;
}

int main() {
    employee_t *e = NULL;

    // for( int i=1; i > 7;i++ ) !!!!

    for( int i = 1; i < 7; i++ )
        e = new_employeEEEE( e, i );

    i = 1;
    for( employee *p = e; p; p = p->next )
        printf( "emp #%d has id: %d\n", i++, p->ID );

    return 0;
}

Output：

emp #1 has id: 6
emp #2 has id: 5
emp #3 has id: 4
emp #4 has id: 3
emp #5 has id: 2
emp #6 has id: 1