Terminate called after throwing an instance - C++ error?

Question

In this program I have a string which I pass as a parameter to a function. I want the function to erase all adjacent letters from a string containing only letters from a-z, always ordered alphabetically. For example if i enter aaabbccd, the program ought to output ad. I want to ask why the program stops working?

#include <iostream>
#include <string>
#include <vector>
using namespace std;
vector<char> rez;
string reduce_string(string s)
{
    for(int i=0; i<s.length()-1; i++)
    {
        if(s[i]==s[i+1])
        {
            s[i]=s[i+1]='0';
            s.erase(i);
            s.erase(i+1);
        }

    }
    return s;
}
int main()
{

    string s;
    cin >> s;
    cout<<reduce_string(s);

    return 0;

}

Can you also state some example inputs with your desired output? — lxop, Jan 24 '18 at 16:42
[Learn how to debug your programs](https://ericlippert.com/2014/03/05/how-to-debug-small-programs/) and it should become obvious. — Some programmer dude, Jan 24 '18 at 16:43

score 0 · Answer 1 · answered Jan 24 '18 at 16:43

0

Your return is inside the loop - the loop will only run on the first character then return.

answered Jan 24 '18 at 16:43

lxop

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score 0 · Answer 2 · edited Feb 09 '18 at 11:37

0

After the first erase(i) all the characters shift one left and the indices change. Instead of calling s.erase(i+1) you have to call again s.erase(i) to not try to access beyond the end of the string:

s.erase(i);
s.erase(i);

or just s.erase(i, 2).

edited Feb 09 '18 at 11:37

Scott

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answered Jan 24 '18 at 21:14

Mihayl

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Terminate called after throwing an instance - C++ error?

2 Answers2