Mysterious Seg. Fault........Spoj ARITH

[ofey]

The following program attempts to work as a calculator for huge inputs.

PROBLEM STATEMENT: http://www.spoj.com/problems/ARITH/

It's working perfectly on IDE for all imaginable cases.

IDE URL: http://ideone.com/lP3JZe

On SPOJ it has started giving SIGSEGV.
I know it may be difficult to read and understand the whole code, but any idea about where this fault may be arising from will be appreciated.
Thanks

/////////////////////////////////////CODE//////////////////////////////////


#include<iostream>
#include<string>
#include<algorithm>
#include<iomanip>
#include<vector>
#define sz size()
using namespace std;


///////////////////////////////////////////////////////////////////////////

string str1Copy(""),strAns;
vector<string> store,storeAdd;

//////////////////////////////////////////////////////////////////////////
/////////////////ADD 2 NUMBERS AND STORE IN strAns////////////////////////

void getSum(string str1,string str2) {
strAns.erase();
if(str2=="0") {
strAns=str1;
return;
}
int carry=0,i=0,j=0,sum=0;
for(i=str1.sz-1,j=str2.sz-1;i>=0&&j>=0;i--,j--) {
sum=(str1[i]-'0')+(str2[j]-'0')+carry;
carry=sum==0?0:sum/10;
sum%=10;
strAns=char(sum+'0')+strAns;
}
while(i>=0) {
sum=carry+(str1[i]-'0');
carry=sum==0?0:sum/10;
sum%=10;
strAns=char(sum+'0')+strAns;
i--;
}
while(j>=0) {
sum=carry+(str2[j]-'0');
carry=sum==0?0:sum/10;
sum%=10;
strAns=char(sum+'0')+strAns;
j--;
}
strAns=carry>0?char(carry+'0')+strAns:strAns;
}
//////////////////////////////////////////////////////////////////////////////
//////////////////////////SUBTRACT 2 NUMBERS/////////////////////////////////

void getDiff(string str1, string str2) {
strAns.erase();
int carry=0,i=0,j,diff=0,temp=0;
for(i=str1.sz-1,j=str2.sz-1;i>=0&&j>=0;i--,j--) {
diff=(str1[i]-'0')-(str2[j]-'0');
if(diff>=0) {
strAns=char(diff+'0')+strAns;
continue;
}
diff+=10;
strAns=char(diff+'0')+strAns;
temp=i-1;
while(str1[temp]=='0') {
str1[temp]='9';
temp--;
}
str1[temp]--;
}
while(i>=0) {
strAns=str1[i]+strAns;
i--;
}
for(i=0;strAns[i]=='0';) //REMOVE STARTING ZEROES
strAns.erase(i,1);
}

/////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////

int main() {
int setwLen=0,cases=0,i=0,pos=0,j=0,caseVar=0;
string str(""),str1(""),str2(""),strDash(""),tempStr1("");
cin>>cases;
for(caseVar=0;caseVar<cases;caseVar++) {
strDash.erase();
str.erase();
str1.erase();
str2.erase();
cin>>str;
pos=str.find_first_of("+-*");

/////////////////////////////////////////////////////////////////////////////
/////////////////////////////////////////////////////////////////////////////
////////////////////ADDITION CASE////////////////////////////////////////

if(str[pos]=='+') {
str1=str.substr(0,pos); //FIRST NUMBER
str2=str.substr(pos+1); //SECOND NUMBER
getSum(str1,str2);

///////////////////////STEPS FOR FORMATTED O/P//////////////////

setwLen=max(strAns.sz,max(str2.sz+1,str1.sz));
cout<<setw(setwLen)<<str1<<"\n";
cout<<setw(setwLen-str2.sz)<<'+'<<str2<<"\n";
//setwLen=max(strAns.sz,str2.sz+1);
//cout<<setfill('-')<<setw(setwLen)<<"-"<<"\n";
for(i=0;i<max(strAns.sz,str2.sz+1);i++)
strDash+='-';
cout<<setw(setwLen)<<strDash<<"\n";
setwLen=max(strAns.sz,max(str2.sz+1,str1.sz));
cout<<setfill(' ')<<setw(setwLen)<<strAns<<"\n\n";
}

//////////////////////////////////////////////////////////////////////////////
/////////////////////////////////////////////////////////////////////////////
//SUBTRACTION//////////////////////////////////////////////////////////////

else if(str[pos]=='-') {
strDash.erase();
str1Copy.erase();
str1Copy=str1=str.substr(0,pos); //FIRST NUMBER
str2=str.substr(pos+1); //SECOND NUMBER
getDiff(str1Copy,str2);

//////////////STEPS FOR FORMATTED O/P//////////////////

setwLen=max(strAns.sz,max(str2.sz+1,str1.sz));
cout<<setw(setwLen)<<str1<<"\n";
cout<<setw(setwLen-str2.sz)<<'-'<<str2<<"\n";
for(i=0;i<max(strAns.sz,str2.sz+1);i++)
strDash+='-';
cout<<setw(setwLen)<<strDash<<"\n";
setwLen=max(strAns.sz,max(str2.sz+1,str1.sz));
cout<<setfill(' ')<<setw(setwLen)<<strAns<<"\n\n";
}
////////////////////////////////////////////////////////////////////////////
/////////////////////////////////////////////////////////////////////////////
//MULTIPLICATION//////////////////////////////////////////////////

else if(str[pos]=='*') {
tempStr1.erase();
strDash.erase();
store.erase(store.begin(),store.end());
storeAdd.erase(store.begin(),store.end());
str1=str.substr(0,pos); //1st NUMBER
str2=str.substr(pos+1); //2nd NUMBER
tempStr1=str1;
for(i=str2.sz-1;i>=0;i--) {
if(str2[i]=='0') {
tempStr1="0";
goto skip;
}
else if(str2[i]=='1') {
tempStr1=str1;
goto skip;
}
for(j=0,tempStr1=str1;j<(str2[i]-'0')-1;j++) {
getSum(tempStr1,str1);
tempStr1=strAns;
}
skip:
store.push_back(tempStr1);
storeAdd.push_back(tempStr1);
}
for(i=1;i<store.sz;i++)
for(j=0;j<i;j++)
storeAdd[i]+='0';
tempStr1=storeAdd[0];
for(i=1;i<store.size();i++) {
getSum(tempStr1,storeAdd[i]);
tempStr1=strAns;
}

////////////////////////STEPS FOR FORMATTED O/P/////////////////////

setwLen=max(tempStr1.sz,max(str1.sz,str2.sz+1));
cout<<setw(setwLen)<<str1<<"\n";
cout<<setw(setwLen-str2.sz)<<'*'<<str2<<"\n";
for(i=0;i<max(str2.sz+1,store[0].sz);i++)
strDash+='-';
cout<<setw(setwLen)<<strDash<<"\n";
for(i=0;i<store.size();i++)
cout<<setw(setwLen-i)<<store[i]<<"\n";
if(store.sz==1)
continue;
strDash.erase();
for(i=0;i<max(tempStr1.sz,store[store.sz-1].sz);i++)
strDash+='-';
cout<<setw(setwLen)<<strDash<<"\n";
cout<<setw(setwLen)<<tempStr1<<"\n\n";
////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////
}
}
return 0;
}

[NwN]

Hi there,

Welcome to the forums :)

My advice:

- wrap the code in code tags: [code] code here [/code]
- place debug statements in the program that trace all steps, then you have an idea at least after which step the segfault occurs.
- Have a look at this article: http://cplusplus.com/articles/iwTbqMoL/

Hope that helps.

All the best,
NwN

[cire]

global variables, goto, obnoxious looking comments, a near complete lack of whitespace, poorly named variables, most of the work done in a monolithic function and a two letter macro that hides function calls.

No wonder you can't debug it?

[ofey]

@NwN: Got the error. Was a slight typo. Thanks anyways.

@cire: i am a noob presently, hence the apparently abhorrent code. Any documentation/reference on writing better, easier to debug code would be most welcome. Thanks.