C Programming - Control Instructions - Discussion

I think statement 3 is right.

int i=5;
for(;i<4;i++)
{
printf("%d",i);
}

It will not print at least one time.

4th option is incorrect as:

for(i=5;i<=2;i++)
printf("%d",i+1);

This won't execute even once.

Anyone tell me, if the above program is false?

For(;;); here is semicolon is present after for then how it became a infinite loop.

@Akash.

Both while and for loop are looks some what same and only difference is for loop looks simple than while, because all expressions are stated in a single for loop, where user can understand easily by looking for.

If we want to execute a statement at least once, whatever the condition is true or false in this case we should use do-while loop instead of for loop. In do-while loop first statement is executed then condition is checked. While in FOR loop first condition is checked then statement is executed.

Only do...while loop can be used to execute statement atleast once.

How is for loop slower than while loop?

The 4th statement is "CAN BE USED" which suggests in some cases not always. If the statement was always be used for executing the body at least once. Then the answer would be "do...while".

Why Statement 4 is true.

For Cannot be executed "at-least once", We can terminate it in the first Conditional comparison.

Example:

for(i=1; i>5 ; i++) {"This will not be executed"}.

And If You are genius enough to make it exec atleast once than I may say that -

It is also Possible for "do-while" NOT to execute even atleast for once.

Example:

do{
break; //below lines will not be executed even for a single run.
}
(I know this is stupidity, but what about other programs given by others? )

Can anyone tell me how while is faster than for loop?