What is wrong with this code? The answer should be 24 for this question right?

Question

What is wrong with this code? The answer should be 24 for this question right?

int t; 
vector<int>arr={24,434};

for(int i=arr.size()-1;i>=(arr.size()-2);i--)
{

        t=i;
}

cout<<arr[t];

Answer 1

This loop

for(int i=arr.size()-1;i>=(arr.size()-2);i--)

is an infinite loop.

When i is equal to 0 it is decremented due to the third expression of the loop and becomes equal to -1.

And then in this condition

i>=(arr.size()-2)

as the operand arr.size()-2 has unsigned integer type with the rank not less than the rank of an object of the type int then due to the usual arithmetic conversions the expression i is converted to the unsigned integer type that corresponds to the type of the expression arr.size()-2 and becomes a very big value due to promoting the bit sign.

That is in this expression

i>=(arr.size()-2)

the left operand can not be a negative value.

In fact this loop

for(int i=arr.size()-1;i>=(arr.size()-2);i--)

does not make a sense because in any case there can be no more than one iteration.