When can I omit curly braces in C?

Question

When can I omit curly braces in C? I've seen brace-less `return` statements before, such as ``` if (condition) return 5; ``` But this doesn't always seem to work for all statements, i.e., when declaring a method. Are the rules for brace omission the same as in Java?

Accepted Answer

The only places you can omit brackets are for the bodies of `if-else`, `for`, `while`, `do-while`, or `switch` statements if the body consists of a single statement:

```
if (cond)
  do_something();

for (;;)
  do_something();

while(condition)
  do_something();

do 
  do_something();
while(condition);
```

However, note that each of the above examples counts as single statement according to the grammar; that means you can write something like

```
if (cond1)
  if (cond2)
    do_something();
```

This is perfectly legal; `if (cond2) do_something();` reduces to a single statement. So, for that matter, does `if (cond1) if (cond2) do_something();`, so you could descend further into madness with something like

```
for (i=0; i < N; i++)
  if (cond1)
    if (cond2)
      while (cond3)
        for (j=0; j < M; j++)
          do_something(); 
```

Don't do that.

When can I omit curly braces in C?

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