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

Both the if and else clauses control only the immediately following statement. Your code, indented correctly, is actually:

#include "simpletools.h"
int main()
{
  while(1)
  {
    print("button = %d\n", input(3));
    if(input(3) == 1) 
      high(14); 
    pause(50);
    low(14);
    pause(50);
  } //while
}   // main

The fact that two statements may be on the same line is irrelevant; the if still only controls a single statement. If you want to control two or more statements, you must wrap them in a "compound statement" by using braces:

#include "simpletools.h"
int main()
{
  while(1)
  {
    print("button = %d\n", input(3));
    if(input(3) == 1) {
      high(14); 
      pause(50);
    } else {
      low(14);
      pause(50);
    }
  } //while
}   // main

Since the else must immediately follow the if's controlled statement, inserting it after your two-statement line without braces won't work.