INTERVIEW QUESTIONS C BRANCHES & LOOPS IN C DETAILS

Question: why n++ executes faster than n+1?

Answer: The expression n++ requires a single machine instruction such as INR to carry out the increment operation whereas, n+1 requires more instructions to carry out this operation.

The expression n++ requires a single machine instruction such as INR to carry out the increment operation whereas, n+1 requires more instructions to carry out this operation. Source: CoolInterview.com

The question is meaningless since the two aren't equivalent.

n++ modifies n.
n+1 does not.

If the purpose is to increment n by one and n is a register variable, the two are almost the same in processor resources, except that the result of n+1 requires the compiler to allocate a second register for the intermediate result.

Also, the first answer is incorrect. The 'INC EAX' instruction in an x86 CPU is no faster than an 'ADD EAX,1' instruction and the only benefit is to reduce code space. Source: CoolInterview.com

Memory related operations takes more time in m+1 it goes to the memory twice ie to search and to store whereas m++ goes only once Source: CoolInterview.com

The expression n++ requires a single machine instruction such as INR to carry out the increment operation whereas, n+1 requires more instructions to carry out this operation.



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The question is meaningless since the two aren't equivalent.

n++ modifies n.
n+1 does not.

Source: CoolInterview.com

Well, it does not!
While we might be tempted to say that 'increment' instruction executes faster than a 'sum' instruction, I have not come across any compiler which uses 'sum' instruction for 'k+1'.
Also, this issue is totally dependent upon the instruction set of the machine (and compiler) for which the code is compiled. So, there is no point in making it a general rule. Source: CoolInterview.com

n++ is unary operation and n+1 is binary operation.unary operation takes less time than binary operation.that is why n++ is faster than n+1 Source: CoolInterview.com

n++ requires less memory as compared to n+1 as well as n++ requires just 1 reg bt n+1 requires one more register to store the answer Source: CoolInterview.com

hi..
n++
and n+=1 both will give the same results but when you compile these instructions seperately, compliler will generate only INR for n++ and
for n += 1 will generate ADD instruction . So this INR instruction is run little smaller than ADD. Source: CoolInterview.com

n++ executes fast then n+1 because n++ takes less machine cycles than n+1. Source: CoolInterview.com

++ is a unary operator while + is a binary operator...
Tecnically speakin, A unary operator works on only one operand...while the binary works on two...this affects the execution time...More the operands...more will be the time of execution... Source: CoolInterview.com

n++ is faster because of the following reasons:

1 simply,n++ is a unary operator and n+1 is a binary operator. unary operator takes less time than binary operator.
2 n++ requires less memory place and n+1 requires more. Source: CoolInterview.com

It's totally Machine dependent or compiler dependent. Source: CoolInterview.com

what is the out put of a+~b Source: CoolInterview.com

Any modern compiler will optimise n=n+1 to n++ Source: CoolInterview.com

n++ is executed more faster the n+1 because the pointer pointing to location n is incremented very easily where as for n+1 the control has to mov to the alu unit and the back to the n location. Source: CoolInterview.com

n++ operator is unary which takes less time to executed as compared to n+1 which is binary operator Source: CoolInterview.com

generally unary operators executes fast.
and n+1, here it needs to perform both increment and assignmentdone seperatly.where as in n++ both are done at a time Source: CoolInterview.com

n++ is a single instruction set but n+1 is a multiple instruction set ,so n++ executes faster then n+1. Source: CoolInterview.com

n++ requires an INC command in assembly
n+1 requires following commands -
MOV R1,1
ADD R1,N
Hence n++ is slow than n+1 as n++ uses only one instruction an n+1 uses two instruction Source: CoolInterview.com

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