# Keep getting runtime errors.

• This code I made keeps getting a runtime error and i'm not sure how to fix it.

``````class Solution {
public:
string addBinary(string a, string b) {

string ans;

bool carry = false;
int max = 0;
int x[a.size()];
int y[b.size()];
int res[a.size()];

if (a.size() > b.size())
max = a.size();

else if (a.size() < b.size())
max = b.size();

else if (a.size() == b.size())
max = a.size();

for(int i = 0;i < max+1; i++){

if(a[i] == '1')
x[i] = 1;
else
x[i] = 0;

if(b[i] == '1')
y[i] = 1;
else
y[i] = 0;
}

for (int j; j < max+1; j++){

if (carry){
x[j]++;
carry = false;
}

if(x[j]+y[j] == 1)
res[j] = 1;

else if(x[j]+y[j] == 0)
res[j] = 0;

else if(x[j]+y[j] > 1){
res[j] = 0;
carry = true;
}
}
switch(res[0]){
case 0: ans = '0';
break;

case 1: ans = '1';
break;
}

for(int k = 1; k < max+1; k++){

switch(res[k]){
case 0: ans = '0';
break;

case 1: ans = '1';
break;
}
}

return ans;
}
};``````

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