What is causing segmentation fault/buss error in this?

general
1

its a test code , i am learning use of stoi()

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#include <iostream>
#include<string>

using namespace std;

int main()
{ 
    int N;

string S,T;

int i,j,A[N],B[N];

cout<<"enter size ";
cin>>N;

cout<<"enter strings ";
cin>>S;

char temp1;
for(i=0;i<N;++i)
{
   if(i==0)
   {
       A[i]=stoi(S,0,2);
       
   }
   else
   {
       temp1=S[i];
       S[i]=S[i-1];
       S[i-1]=temp1;
       
       A[i] = stoi(S,0,2);
       
   }
   
}
cout<<"all formations are ";
for(i=0;i<N;++i)
{
    cout<<A[i]<<endl;
}
    

    return 0;
}
2

You’re defining A and B to be arrays of N elements when you haven’t initialised N yet.

1 Like
3

oh …thanks bro

1 Like
4

one question i have ,is it compusory to define modulo in question where it is mention modulo is 1000000007 or program will run without it

5

You should define and use it as the question states, otherwise you’ll get the wrong answer :slight_smile:

6

like for smaller value you don’t need modulo.

7

If it’s guaranteed that the correct answer is never \ge the modulus, then you can leave it out, if you want.

2 Likes
8

ok.thank you again

1 Like
9

if you use modulo for smaller values it wont affect the answer, but for bigger values you have to use.
So it is good to put modulo if mentioned for all the answers.

1 Like
10

so nice of you bro .i have some doubts which i will ask once the challenge is over