Syntax

logical-OR-expr ? expr : conditional-expr

Remarks 

The conditional operator ?: is a ternary operator.  

In the expression E1 ? E2 : E3, E1 evaluates first. If its value is true, then E2 evaluates and E3 is ignored. If E1 evaluates to false, then E3 evaluates and E2 is ignored. 

The result of E1 ? E2 : E3 will be the value of either E2 or E3 depending upon which evaluates. 

E1 must be a scalar expression. E2 and E3 must obey one of the following rules:

• 1. Both of arithmetic type. E2 and E3 are subject to the usual arithmetic conversions, which determines the resulting type.
• 2. Both of compatible struct or union types. The resulting type is the structure or union type of E2 and E3.
• 3. Both of void type. The resulting type is void.
• 4. Both of type pointer to qualified or unqualified versions of compatible types. The resulting type is a pointer to a type qualified with all the type qualifiers of the types pointed to by both operands.
• 5. One operand is a pointer, and the other is a null pointer constant. The resulting type is a pointer to a type qualified with all the type qualifiers of the types pointed to by both operands.
• 6. One operand is a pointer to an object or incomplete type, and the other is a pointer to a qualified or unqualified version of void. The resulting type is that of the non-pointer-to-void operand.