Why does this if statement require brackets?

Question

Usually, if I follow an if statement with a single statement, I won't need brackets. For example:

if (condition) statement1; statement2;

statement2 will run in any case. But that doesn't happen here:

for (j = 0; j < size; j++) {
    if (size % 2) if (j % 2) *(minmat + j) *= -1.0;        
    else {
        …
    }
}

The else statement is supposed to associate with the first if statement, but it in fact associates with the second. To correct it, I have to do this:

for (j = 0; j < size; j++) {
    if (size % 2) { if (j % 2) *(minmat + j) *= -1.0; }
    else {
        …
    }
}

But why does that happen, when in the first case it's “implied” that the second if statement is inside brackets?

Answer 1

An else statement will associate with the most recent if. You could also correct it like this:

for(j=0; j<size; j++{
    if(size%2) if(j%2) *(minmat+j) *= -1.0; else;        
    else {
        .
        .
        .
    }
}