No output during array matching

Question

I am trying to check two arrays if they are equal are not, if they are not equal print the corresponding text. I did this but i don't get any output or errors from this code. what did i do wrong in this?

typedef struct payl{
    int arrayp[5] = {1,2,3,4,5};
}payl;
typedef struct expected{
    int arraye[5] = {1,2,3,4,6};
}expected;

int main()
{
    payl* pay;
    expected* Ez;
    int itr = (sizeof(pay->arrayp)/sizeof(pay->arrayp[0]));
    int eitr = (sizeof(Ez->arraye)/sizeof(Ez->arraye[0]));
    for(int i=0; i>itr; i++){
        for(int j=0; j>eitr; j++){
            if(pay->arrayp[i] != Ez->arraye[j]){
                cout<<"incorret matching"<<pay->arrayp[i]<<"!="<<Ez->arraye[j]<<endl;
            }
        }
    }
    return 0;
}

I know they are other ways to do this, but i want to know what i did wrong in this. Thank you.

Answer 1

First of all, pay and Ez are pointers, but you never make them point anywhere valid. This is undefined behavior, and will likely result in a segmentation fault or do something different entirely. Change this:

payl* pay;
expected* Ez;

To this:

payl* pay = new payl;
expected* Ez = new expected;

And don't forget to delete them in the end:

delete pay;
delete expected;

Also, your comparisons don't work this way. Instead of this:

for(int i=0; i>itr; i++){
   for(int j=0; j>eitr; j++){ 

You should wap that > around and do this instead:

for (int i = 0; i < itr; i++) {
    for (int j = 0; j < eitr; j++) {

With those changes, it correctly prints every instance of every element in each array that's not the same as a different element. Which means not just that last one where there's a 5 in one and a 6 in another. That's not how you check whether two arrays are equal. Instead, the loop should look like this:

for (int i = 0; i < itr; i++) {
    if (pay->arrayp[i] != Ez->arraye[i]) {
        cout<<"incorret matching"<<pay->arrayp[i]<<"!="<<Ez->arraye[j]<<endl;
    }
}