my code is running well during execution...but i when i go to submit its show segmentation fault

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Given an array C of size N-1 and given that there are numbers from 1 to N with one element missing, the missing number is to be found.

Input:

The first line of input contains an integer T denoting the number of test cases. For each test case first line contains N(size of array). The subsequent line contains N-1 array elements.

Output:

Print the missing number in array.

Constraints:

1 ≤ T ≤ 200

1 ≤ N ≤ 107

1 ≤ C[i] ≤ 107

Example:

Input:

2
5
1 2 3 5
10
1 2 3 4 5 6 7 8 10

Output:

4
9

i have done this in c++

#include <iostream>
using namespace std;

int main() {
int a,n,arr[50],j=1,element;
int sum,total[50],i;
cin>>n;
a=n;
while(n!=0)
{
    cin>>element;
    sum=0;
    total[j]=0;
    for(i=1;i<=element-1;i++)
    {
        cin>>arr[i];
        sum=sum+arr[i];
    }
    total[j]=(element*(element+1)/2) -sum;
    j++;
    n--;
}
for(i=1;i<=a;i++)
{
    cout<<total[i]<<endl;
}
return 0;
}

Output:

4
9

Because you have declared the array of size 50 blocks.

But , according to given constraints : 1 ≤ N ≤ 107 , 1 ≤ C[i] ≤ 107

if you take value of element more than 50 , it will give segmentation fault because the maximum size of array is 50.

So , increase the size of arrays to arr[107]; and total[107];

And then submit the solution , it would work then.

Identify what's causing segmentation faults (segfaults), A segmentation fault (aka segfault) is a common condition that causes programs to crash; they are often associated with a file named core . non-existent array element, not properly defining a pointer before using it, or (in C have to run the program under debugger control, and then step through the code� I am writing a cross-platform C++ program for Windows and Unix. On the Window side, the code will compile and execute no problem. On the Unix side, it will compile however when I try to run it, I get a segmentation fault. My initial hunch is that there is a problem with pointers. What are good methodologies to find and fix segmentation fault

Try this as a test case:

2
55
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55
55
33 54 1 55 23 51 35 5 49 26 43 42 41 32 7 14 9 50 34 29 37 25 52 24 8 53 15 45 44 19 39 47 17 48 38 21 36 31 3 18 46 20 6 27 12 11 16 10 2 13 28 4 30 22

your code should then crash under your control, and then you can find out why.

Think hard about the constraints you were given for various values and how your code operates at the edges of those constraints.

Also, there is a way to solve this problem that doesn't require you to use any arrays at all. It's the fastest way to solve the problem.

Segmentation fault when running, but success when debugging , Try the following steps: type ulimit -c unlimited in an xterm (this allows the creation of core/postmorterm files). launch your program (and let it� I commented out the line containing the function call I had just entered and recompiled. Everything worked fine. This is very similar to the old segmentation fault. Before your fix, I fixed them by adding code around the code that was causing the fault. Could the segmentation fault problem still be in 1.6.21 and is simply not reported as an error?

One of the best solution for finding Missing element is using XOR operator :

Question: You are given a list of n-1 integers , And these integers are in the range of 1 to n. There are no duplicates in the list . One of the integer is missing in the list. Now, we need to find that missing number.

Solution :

Method 1 : By finding sum of first "n" natural numbers.

Step 1 : First, find the sum of all numbers from 1 to n ( means find the sum of first "n" natural numbers)

Step 2 : Subtract each element (all elements) of the given list from the sum. And we’ll get the missing number.

Note : There might be an integer overflow while adding large numbers in method 1 solution.

Method 2: Using XOR operator :

Remember these properties : n ^ n = 0 AND n ^ 0 = n

Step 1: We’ll take the xor of all numbers from 1 to n (Means, we’ll take xor of first "n" natural numbers).

Step 2: We’ll take the xor of all elements of the given array (list).

Step 3: xor of Step 1 and Step 2 will give the required missing number.

Example : Given list arr = [4,2,1,6,8,5,3,9] n=9 (given)

Step1 : Step1_result = 1 ^ 2 ^ 3 ^ 4 ^ 5 ^ 6 ^ 7 ^ 8 ^ 9 = 1

Step2 : Step2_result = 4 ^ 2 ^ 1 ^ 6 ^ 8 ^ 5 ^ 3 ^ 9 = 6

Step3 : Final_Result = Step1_result ^ Step2_result = 1 ^ 6 = 7

But, How Final_Result calculated the missing number ?

Final_Result= ( 1 ^ 2 ^ 3 ^ 4 ^ 5 ^ 6 ^ 7 ^ 8 ^ 9 ) ^ ( 4 ^ 2 ^ 1 ^ 6 ^ 8 ^ 5 ^ 3 ^ 9 )    

So , here ,

Final_Result = (1 ^ 2 ^ 3 ^ 4 ^ 5 ^ 6 ^ 7 ^ 8 ^ 9 ) ^ ( 4 ^ 2 ^ 1 ^ 6 ^ 8 ^ 5 ^ 3 ^ 9 )

= 1 ^ 2 ^ 3 ^ 4 ^ 5 ^ 6 ^ 7 ^ 8 ^ 9 ^ 4 ^ 2 ^ 1 ^ 6 ^ 8 ^ 5 ^ 3 ^ 9

= ( 1 ^ 1 ) ^ ( 2 ^ 2 ) ^ ( 3 ^ 3 ) ^ ( 4 ^ 4 ) ^ ( 5 ^ 5 ) ^ ( 6 ^ 6 ) ^ (7) ^ ( 8 ^ 8 ) ^ ( 9 ^ 9 )

= 0 ^ 0 ^ 0 ^ 0 ^ 0 ^ 0 ^ 7 ^ 0 ^ 0 ( property applied )

= 0 ^ 7 ( because we know 0 ^ 0 = 0 )

= 000 ^ 111

= 111

= 7 ( Required Result )

Segmentation fault, In computing, a segmentation fault (often shortened to segfault) or access violation is a fault, On systems using hardware memory segmentation to provide virtual memory, a segmentation fault occurs when the At the level of code errors, this occurs when the program writes to part of its own code segment or the read-only� The error you get is segmentation fault (segfault). Default action is to kill your process (crash the program, possibly dump a core file for post-mortem diagnostics/debugging). 99% of the time when you debug it you find your object was not initialized, your variable has a bad value in it, bad enough to crash the program.

Debugging Segmentation Faults - hpc, System call checks the arguments in the user program, The first stage is loaded and executed by the BIOS from the prefix running in numerical order) presenting the user The new processes may go on creating new the file system with a root dentry and its child entries. From last 1 week I have been searching like crazy and changed my code so many times to make it work and couldn’t find the solution. Finally your resolution helped and my code is running perfectly now. I just did Ctrl + Break 10-15 times as you suggested and now all problems resolved thanks to you.

Segmentation Fault, And then we run it and get a nasty segmentation fault: Sign in to The next step is to run the program and reproduce the segmentation fault. To do this The problem is in the sixth line of source code, as shown in the image, our printf line. This means that we can hook into their execution, but we will not see any symbols. Preprocessing - processing include files, conditional compilation instructions and macros. Compiling - generating assembler source code. Assembling - generating machine code and creating object files, Linking - linking one or more object files

Why does the ctcreate code give the error SIGSEGV: Segmentation , Program received signal SIGSEGV: Segmentation fault - invalid memory and it did not have anything to do with program itself (except for not too good error I tried as first step to go slowly through input and double checked everything in it. Also check the name of your file for typos, and folder in which you are running it � The core file is normally called core and is located in the current working directory of the process. However, there is a long list of reasons why a core file would not be generated, and it may be located somewhere else entirely, under a different name.

Comments
  • Look at the constraints, and look at the sizes of the arrays you declared, and I think you'll see the problem.
  • Nice way to solve the problem BTW, although you don't need the total array. Just output each result as you get it, instead of putting them all in an array and outputting them at the end.
  • If n is 50 or more, total[j] will perform access beyond the array limit... Indexing in C starts from 0.
  • Why have you included "python" tag ??
  • @VishalSrivastav I've deleted python and C
  • 1 ≤ T ≤ 200 so total needs to be total[201] given the code as is (or it could just be eliminated)
  • i have change peremiter from 50 to 500...thanks to u..i forget to look at constraints now my code is working fine..one problem is their ..while submitting its showing me Wrong Answer. !!!Wrong Answer Possibly your code doesn't work correctly for multiple test-cases (TCs). The first test case where your code failed: Input: 5 1 2 3 5 Its Correct output is: 4 And Your Code's output is: 501
  • and i have run by code its working fine....but while submitting they showed and error... Wrong Answer. !!!Wrong Answer Possibly your code doesn't work correctly for multiple test-cases (TCs). The first test case where your code failed: Input: 5 1 2 3 5 Its Correct output is: 4 And Your Code's output is: 501
  • @user11249680 - You actually have the bones of the correct answer in your answer. You're doing a lot more work than you need to.
  • This doesn't answer the original poster's question at all. And additionally, just gives the original poster an alternate answer to a problem. This is clearly a problem from some coding problem website. Giving them the answer is the opposite of helpful. The point of those websites is so you can figure out the answer yourself. Lastly, your answer is less efficient than it could be for either method you chose.
  • Though the xor method is clever. I'll give you that. Though, given that an alternate set of operations for binary numbers that allows all algebraic operations to work is to use xor for add, the two methods are basically equivalent formulations of the same solution, just using different numeric fields.