anybody please help something. wrong in this code

include

include

include

include

using namespace std;

int main() { long int m,n,i,l=0,l2=0,j; int temp,c=0; string st; cin>>m>>n;

char u[n][m+10],a[m],b[m],t;

cin>>a>>b;

for(i=0;i<n;i++)
{
    cin>>u[i];
}
    stringstream s;

for(i=0;i<n;i++)
{

    long int si=strlen(u[i]);

    for(j=0;j<5;j++)
    {
        st+=t;
    }

    if(st=="set_a")
    {

    for(j=6;u[i][j]<' ';j++)
    {
        t=u[i][j];
        s<<t;
        s>>temp;
        l=l*10+temp;

    }

    while(j<si)
    {
        t=u[i][j];
        s<<t;
        s>>temp;
        l2=l2*10+temp; 
    }

    a[si-l-1]=l2;
}

if(st=="set_b")
    {

    for(j=6;u[i][j]<' ';j++)
    {
        t=u[i][j];
        s<<t;
        s>>temp;
        l=l*10+temp;

    }

    while(j<si)
    {
        t=u[i][j];
        s<<t;
        s>>temp;
        l2=l2*10+temp; 
    }

    b[si-l-1]=l2;
}
if(st=="get_c")
{

        vector<int> y;
        for(j=n;j>=0;j--)
        {
            if(a[j]=='1'&&b[j]=='1'&&c==1)
            {

                y.push_back(1);

            }

            if(a[j]=='1'&&b[j]=='1'&&c==0)
            {
                y.push_back(0);
                c=1;
            }

            if((a[j]=='1' && b[j]=='0' && c==1)||(a[j]=='0' && b[j]=='1' && c==1))
            {
                y.push_back(0);

            }

            if((a[j]=='1' && b[j]=='0' && c==0 )||(a[j]=='0' && b[j]=='1' && c==0)||(a[j]=='0' && b[j]=='0' && c==1))
            {
                y.push_back(1);
                c=0;

            }

            if((a[j]=='0' && b[j]=='0' && c==0 ))
            {
                y.push_back(0);

            }


        }

    for(j=6;u[i][j]<' ';j++)
    {
        t=u[i][j];
        s<<t;
        s>>temp;
        l=l*10+temp;

    }

    cout<<y[si-l-1];

}

}

}