C language: if() with no else(): using braces fails

Question

I\'m confused on need for braces after IF() expression. When using IF(){...}ELSE{...} I\'m used to using braces around both IF and ELSE blocks. But when I use no ELSE block it

Answer 1

If input(3)==1 then high(14); will be called.

But pause(50);low(14);pause(50); will always be executed despite the return from input(3)