what does sequence point means?

[Sonam Goenka]

Hi All,

I have one query to discuss with you. I am studying C programming language. In which I am totally getting confused about "sequence point" concept of the C programming. I don't what is the use this 'sequence point' in C programming. If you know anything about "sequence point" , then please let me know the same. Your help would be greatly appreciated.

[Katty]

Modifying the same variable and using its old value for anything other than computing the new value, without a sequence point in between, causes undefined behavior. A sequence point is a point of time in the evaluation of a C expression,where all side effects are guaranteed to have taken place. Sequence point is the Standard's attempt to define when certain sorts of optimization may and may not be permitted to be in effect.

[kelfro]

A sequence point is nothing but point within a execution of program at which it is guaranteed that all side effects of previous evaluations will have been performed, and no side effects from subsequent evaluations have yet been performed. The point (at the end of a full expression, or at the ||, &&, ?:, or comma operators, or just before a function call) at which all side effects are guaranteed to be complete.

[Zecho]

Hello friends,

The sequence points in C programming include following:

• The && and || operators,
• The , (comma) and ?: (conditional) operators,
• The semicolon at the end of a statement, and

[Reegan]

A sequence point is point in a computer program's execution at which it is confirmed that all side effects of previous evaluations will have been performed. And there is no side effects from subsequent evaluations have yet been performed. Sequence points also come into play when the same variable is modified more than once. They are often mentioned in reference to C and C++, because the result of some expressions can depend on the order of evaluation of their sub expressions. Adding one or more sequence points is one method of ensuring a consistent result, because this restricts the possible orders of evaluation.

[opaper]

The"sequence points" is an object's value that can be modified only once by an expression. A sequence point is a point of time in the evaluation of a C expression, where all side effects are guaranteed to have taken place. Most importantly, the assignment operators (such as =), the post and pre decrement/increment operators (++ and --), and the comma *separator* in parameter lists are NOT sequence points.