hey
whay the output is 1 ?
int a=1;
int b=1;
int c= a || --b;
printf ("%d",b);
but in bellow code output is 0 ?
int a=0;
int b=1;
int c= a || --b;
printf ("%d",b);
All right apart from the edited question, I have to admit that the two results are different.
The reason is that the logical OR || return 1 when at least one of the operands is non-zero.
And if the first operand is not a 0, the second part is not going to be read.
This "bug/feature" is known as a sequence point error caused by short circuit evaluation. The logical OR operator creates a sequence point. Unfortunately , due to short circuit evaluation, in the first example the --b expression never gets evaluate. As a consequence of this printf("%d", b); will print 1 since b was never decremented.
In the second example the --b expression is evaluated because a is 0. Consequently, b is 0 as shown in the print statement.
The moral of the story is NEVER use auto increment/decrement operators with other sequence point operators. It is always best to use auto increment/decrement operators in single statements.
You edited your question
In the original question you said the first code gives 0 and the second 1
But actually they are kind of the same code and the result is 0 for both.
