Inline
An inline function is just like any other function in C++ and is also called in the regular way. The function it performs is that it creates a copy of the compiled function definition. That is, it creates a copy of the defined items to compile. An example can be taken if we are adding any two integers and call it the inline function, the compiler will create a copy of the integers to be compiled.
Example:
Inline int sum (int x, int y)
{
Return (x+y);
}
Macro
Macros in C++ implement text replacement in a program line. That is, they replace text according to the change defined in the function. Unlike inline as a function, a macro manipulates the code using a function. For example:
#define DOUBLE(X) X*X
int y = 5;
int j = DOUBLE (++y);
Here, we will get the value as 30! As the calling has been done via a macro, “X” has been replaced with ++y which makes ++y to be multiplied by another ++y. This makes a total of 5*6 that is 30 not 6. Six would be the basic but a wrong answer.
Now, macros might be causing a bug here. So an inline function comes to the rescue by copying the values to the compilers’ memory and then compiling it.
Summary:
1.An inline function creates a copy of the function definition.
2.A macro replaces the text as identified and defined within the function.
3.An inline function is also applied when a macro is supposed to cause a bug in the program.
