The advantage of an inline function is that it eliminates the function calls completely, thus improving the performance wherever those calls appear. The disadvantage is that it increases code size, which can be detrimental to performance. For this reason, declaring a function for inline expansion is merely a hint to the compiler. If the increased code size would be detrimental, the compiler is free to ignore the inline declaration and retain the function call instead.
While the programmer is free to manually expand their own functions, this only serves to increase maintenance should the function ever need to be changed, and could lead to errors should those changes not be propagated correctly. The advantage of having a function, even if it is only ever called once (or from within a loop), is to simplify your code and make it easier to read and maintain. If the function is simple, or is called seldom, then it is a good candidate for expansion, but its almost always better to let the compiler decide which functions should be inline expanded.
Outline is the opposite of inline. An inline expanded function is any function or class method where the declaration also provides the definition (the implementation). This is known as implicit inline expansion. Where the definition is kept separate from the declaration, you may use the inline keyword to specifiy that the function should be inline. This is known as explicit inline expansion. Inline expanded functions (whether implied or explicit) does NOT mean the function will in fact be inline expanded. It is merely a suggestion to the compiler. If the compiler's optimisers determine that there is no advantage to be gained by inline expanding a particular function, then that function becomes an outline function. Inline expansion simply means that the body of the function is inserted in place of the function call. Function calls are expensive in terms of memory and performance, so by eliminating the function call completely, your code performs faster and uses less memory. However, functions that are called many times throughout your code will result in a much larger code size, and large code runs slower than small code. Thus the benefit of eliminating a function call has to be weighed against the increased code size. Although some compilers do allow you to override the compiler's inline expansion optimisers, this is strictly non-standard. The best judge of what to expand and what not to expand is best left in the hands of the compiler, and indiscriminate use of the inline keyword should generally be avoided.
Virtual functions have many advantages, but here are a couple of their disadvantages:slower -- The function call takes slightly longer due to the virtual mechanism,and it also makes it more difficult for the compiler to optimize because it doesn't know exactly which function is going to be called at compile time.harder to debug -- In a complex system, virtual functions can make it a little more difficult to figure out where a function is being called from. Or, to figure out why a function isn't being called if someone overrode it with a new virtual function.
... double squareOf_Number(double Number){return (Number*Number);}...int main(){...double Number = 0;...printf("Enter a number: ");cin >> Number;...printf("Square of %f is %f\n", Number, squareOf_Number(Number));...}Or you can include #include and use the function pow(double a, double b) which returns a^b.
Right angles are always 90 degrees. There is no need to calculate this; an angle is either 90 degrees or it is not. The following inline function is all you really need: inline const bool IsRightAngle(double angle) { return(angle==90.0); }
No. A branch is akin to a goto statement in procedural programming. The code branches off to a new code segment, never to return. A function call is akin to a subroutine in structured programming. When the subroutine is finished, control is returned to the instruction immediately following the function call, just as if the function's code were inline expanded at the call site.
yes,we can make function inline
Outline is the opposite of inline. An inline expanded function is any function or class method where the declaration also provides the definition (the implementation). This is known as implicit inline expansion. Where the definition is kept separate from the declaration, you may use the inline keyword to specifiy that the function should be inline. This is known as explicit inline expansion. Inline expanded functions (whether implied or explicit) does NOT mean the function will in fact be inline expanded. It is merely a suggestion to the compiler. If the compiler's optimisers determine that there is no advantage to be gained by inline expanding a particular function, then that function becomes an outline function. Inline expansion simply means that the body of the function is inserted in place of the function call. Function calls are expensive in terms of memory and performance, so by eliminating the function call completely, your code performs faster and uses less memory. However, functions that are called many times throughout your code will result in a much larger code size, and large code runs slower than small code. Thus the benefit of eliminating a function call has to be weighed against the increased code size. Although some compilers do allow you to override the compiler's inline expansion optimisers, this is strictly non-standard. The best judge of what to expand and what not to expand is best left in the hands of the compiler, and indiscriminate use of the inline keyword should generally be avoided.
five plus five = ten
#include<iostream> using namespace std; inline int max(int a,int b) { return (a>b)?a:b; } int main() { int i1=3,i2=5; cout<<endl<<"Inline function says max is "<<max(i1,i2); return 0; } /* Usually when a function is called, the compiler goes to the particular piece of code and executes it. But in the case of inline functions, the code from the body of the function is effectively pasted at the point of call. inline functions are used when the body of the function is only a line or so.*/
The C++ compiler will implicitly (automatically) mark functions for inline expansion whenever you define a function within its own declaration. If functions are declared and defined separately (even in the same file) then they are not implicitly marked for inline expansion. To enable inline expansion for these definitions, you must explicitly mark the definition (not the declaration).
The advantage of full cost plus pricing is the higher return on investment. The disadvantage of full cost-plus pricing is lower demand for the products.
Virtual functions have many advantages, but here are a couple of their disadvantages:slower -- The function call takes slightly longer due to the virtual mechanism,and it also makes it more difficult for the compiler to optimize because it doesn't know exactly which function is going to be called at compile time.harder to debug -- In a complex system, virtual functions can make it a little more difficult to figure out where a function is being called from. Or, to figure out why a function isn't being called if someone overrode it with a new virtual function.
... double squareOf_Number(double Number){return (Number*Number);}...int main(){...double Number = 0;...printf("Enter a number: ");cin >> Number;...printf("Square of %f is %f\n", Number, squareOf_Number(Number));...}Or you can include #include and use the function pow(double a, double b) which returns a^b.
Right angles are always 90 degrees. There is no need to calculate this; an angle is either 90 degrees or it is not. The following inline function is all you really need: inline const bool IsRightAngle(double angle) { return(angle==90.0); }
No. A branch is akin to a goto statement in procedural programming. The code branches off to a new code segment, never to return. A function call is akin to a subroutine in structured programming. When the subroutine is finished, control is returned to the instruction immediately following the function call, just as if the function's code were inline expanded at the call site.
When you mark function as inline compiler puts the whole body of function in those places it is called, similar idea as in macros. If you do not mark function as inlinecompiler inside still decides which functions should be inline and which not. Inline function is less performance costly especially if function is called very often. Why it is lest performance costly? Because to invoke function you need to prepare parameters, put them to stack, make jump and etc. and all those steps are eliminated if function is inline.Example (very basic):inline int sum(int a, int b) {return a + b;}int c, d;c = sum(2, 3); /* compiler will change to 2 + 3 */d = sum(2, 5); /* this one will be changed to 2 + 5 */Full inline functions are allowed in ANSI/ISO C99.
Macros are not actually part of the C++ language; they are nothing more than a simple text-replacement system intended to simplify your coding. Macros do not adhere to C++ type safety and cannot be debugged because macros are preprocessed, prior to compilation. Your compiler can only see the preprocessed code, not the original source code, and therefore cannot debug macros because the macros no longer exist at that point. Inline functions are functions that can be debugged like any other function, but the compiler is able to eliminate the overhead of function calla by replacing those calls with inline expanded code. This is not unlike a macro, which is by definition inline expanded, but retains the built-in type safety and debugging capabilities of the C++ language itself. Typically, if you can use an inline function (or C++ is general) then that is always the preferred option. But if a macro can achieve more than can be achieved with C++ alone, or can otherwise simplify the equivalent C++ code, then use a macro. Just keep in mind that macros are not type-safe and cannot be debugged by the C++ compiler.