Stack smashing detected, core dumped [closed] - c

Question

Closed. This question needs debugging details. It is not currently accepting answers.
Edit the question to include desired behavior, a specific problem or error, and the shortest code necessary to reproduce the problem. This will help others answer the question.
Closed 4 years ago.
Improve this question
#include<stdio.h>
#define MAXSIZE 10
#define OK 1
#define NOK 0
int check_validity(int);
void input_array_elements(int,int *);
void Display_array_elements(int,int *);
int main()
{
int array[MAXSIZE];
int i,num,negative_sum=0,positive_sum=0;
float total=0.0,average;
printf("Enter the value of N\n");
scanf("%d",&num);
while(1)
{
int Return_val;
Return_val=check_validity(num);
if(Return_val == OK)
{
printf("sizeof array=%d\n",sizeof(array));
break;
}
else
{
printf("please enter a value <= 10\n");
scanf("%d",&num);
}
}
input_array_elements(num,&array[MAXSIZE]);
Display_array_elements(num,&array[MAXSIZE]);
}
int check_validity(int num)
{
if(num<MAXSIZE)
{
printf("OK\n");
return OK;
}
else
{
printf("NOK\n");
return NOK;
}
}
void input_array_elements(int num,int *array)
{
int i;
for(i=0;i<num;i++)
{
scanf("%d",&array[i]);
}
}
void Display_array_elements(int num,int *array)
{
int i;
for(i=0;i<num;i++)
{
printf("array[%d]=%d\n",i,array[i]);
}
}
What is "stack smashing"? How to solve this problem?
I'm compiling my program and I'm having error:
* stack smashing detected *: ./a.out terminated Segmentation fault (core dumped)
I don't know what I'm doing wrong.

Answer 1

The pointer to &array[MAXSIZE] is a pointer to one beyond the end of the array. That means your functions will start out of bounds of the array which leads to undefined behavior. The system detects is as a "stack smash" and crashes your program.
If you want to pass a pointer to the first element then use either &array[0], or plain array (as that will decay to &array[0]).

Answer 2

Segmentation fault (or stack smashing as you are getting) happens when you try to access a memory that is not accessible to your program or process.
In your function Display_array_elements I guess you are trying to print the array elements. The second argument should provide the address to the beginning of the array.
By passing &array[MAXSIZE] you are already pointing to the last element and then trying to access the other elements on this array, which is beyond valid array bounds. This is the reason for segmentation fault.
Change this call to one of the below
Display_array_elements(num,&array[0]);
OR
Display_array_elements(num,array);

Answer 3

Segmentation error comes when allocated memory space exceeds by a variable. Once variable declared, amount of memory is allocated in the stack.
Your array causing the problem. Hence array is defined to a particular size, next insertions going above the space and try to access the space of onother variable/ instruction.