Double For loop does not give the expected results?

Question

Why does the j index start from 2 not 1 in this double For loop

For[i = 1, i <= 2, i += 1, For[j = 1, j <= 2, j += 1; Print[{i, j}]]]
{1,2}
{1,3}
{2,2}
{2,3}

Answer 1

The syntax for a For loop is:

For[start,test,incr,body]

But you wrote for "j":

For[start,test,incr; body]

note the ";". If you replace ; by , it works:

For[i = 1, i <= 2, i += 1, For[j = 1, j <= 2, j += 1, Print[{i, j}]]]