进程退出，返回值 3221225477

Question

i am writing this code:

#include<stdio.h>
#include<stdlib.h>
int main()
{
FILE *fp;
int i;
fp = fopen("keimeno.txt","r");
fscanf(fp,"%d",i);
printf("%d\n",i);
    fclose(fp);
return 0;
}

and the file contains:

2
Yiannis Ioannou 356
3
Today
10347
If
345
And then none
1542
John Smith 743
2
My story
3940
Feedback
682
END

When I try to run it, it exits me value 3221225477 instead of printing the number 2..

Can anyone explain why?

Answer 1

When you scan a number, you need to pass the address of the variable where you want to store the result:

fscanf(fp,"%d",&i);

where you have

fscanf(fp,"%d",i);
               ^  missing the & sign!

Your compiler really ought to have warned you - do you enable warnings when you compile?

What is happening here is that the fscanf function writes to the location given (in your case, it writes to whatever location is pointed to by the value of i , instead of writing to the location of i ) . This can corrupt your memory in all kinds of nasty ways - resulting, in your case, in the program "running" for considerable time before crashing.

As @Brandin pointed out, there is a further problem with your code (although it's less likely to be the source of your problem). When you attempt to open a file, you should ALWAYS check that you succeeded. You do this with something like this:

#include <assert.h>
// at the top of the program


// attempt to open the file:
fp = fopen("keimeno.txt","r");
// and check whether you succeeded:
assert(fp != NULL); // this says "check fp is not NULL. Otherwise, quit."

Alternatively, you can make things a bit prettier with:

const char *fileName = "keimeno.txt";
const char *mode = "r";
if((fp=fopen(fileName, mode))==NULL) {
  printf("cannot open file %s\n", fileName);
  return -1;
}

It is almost always a good idea to put "hard wired values" near the start of your program, rather than embedding them in a function call.

Answer 2

Same of my problem. I empty my list and added a new value the it resulted to the value I've entered with another values and ended with an error "process-exited-with-return-value-3221225477"

#include <iostream>
#include <stdlib.h>

using namespace std;

struct Node {
   int data;
   struct Node *left;
   struct Node *right;
};
int count = 0;
struct Node*front = NULL;
struct Node*rear = NULL;

void enqueue(int val) {
    count++;
   struct Node* newnode = new Node; //= (struct Node*) malloc(sizeof(struct Node));
   newnode->data = val;
   if (front == NULL) {
        front = rear = newnode;
        newnode->right=newnode->left;
        newnode->left=newnode->right;
   }
   else {
    rear->right = newnode;
    newnode->left = rear;
    rear = newnode;
    front->left = rear;
    rear->right = front;
   }
}

void dequeue() {
   if(front==NULL)
      cout<<"There is no element yet. Cannot be dequeue."<<endl;
   else {
      if (front == rear) {
        cout<<"The dequeued element is "<< front->data <<endl;
        front = rear = NULL;
         delete front;
         }
      else {
      cout<<"The dequeued element is "<< front->data <<endl;
       struct Node *curr = front;
       front = front->right;
       front->left = rear;
       rear->right = front;
       delete curr;

       }
   }
}

void display() {
   int i;
   struct Node* ptr;

   if(front==NULL) {
      cout<<"The List is empty, nothing to display.";
      cout<<endl;
      return;
  }    
      ptr = front;
      cout<<"Element/s : ";
      for (i=0;i<count; i++) {
         cout<< ptr->data <<" ";
         ptr = ptr->right;
     }
        if (ptr->right==rear) {
            cout<< ptr->data << " ";
        }
       cout<<endl;
}

int main() {
   int ch, val;
   cout<<"1) Enqueue"<<endl;
   cout<<"2) Dequeue"<<endl;
   cout<<"3) Display"<<endl;
   cout<<"4) Exit"<<endl;
   do {
      cout<<"Enter your choice: "<<endl;
      cin>>ch;
      switch(ch) {
         case 1: {
            cout<<"Enter the value of the element:"<<endl;
            cin>>val;
            enqueue(val);
            cout<<endl;
            return main();
            break;
         }
         case 2: {
            dequeue();
            cout<<endl;
            return main();
            break;
         }
         case 3: {
            display();
            cout<<endl;
            return main();
            break;
         }
         case 4: {
            cout<<"Exit"<<endl;
            break;
         }
         default: {
            cout<<"Invalid Choice"<<endl;
         }
      }
   }while(ch!=4);
      return 0;
}

Answer 3

Mate, I am so grateful for posting this. I haven't used scanf for a while and it saved me from pointlessly wasting my time trying to figure out where the problem could be and step-by-step debugging. TY so much! It is not even the first time I am visiting that blog

Answer 4

exited_return_value-3221225477是由于各个编译器的gnu逻辑错位导致的编译器代码错误的高度抽象错位。同一代码将在另一个系统中执行。该值称为系统调用（）错误...