CODEWITHSUNDEEP
cfor-loopwarnings
aytee17
aytee17

Reputation: 415

C Warning: Statement with no effect

When trying to compile my prgram with:

gcc -pedantic -Wall -ansi

I get the warning: warning: statement with no effect

Referring to this line:

for(currentDirection; currentDirection <= endDirection; currentDirection++)

Can anyone help me with this?

Upvotes: 16

Views: 61452

Answers (3)

Cody Syring
Cody Syring

Reputation: 13

In my experience this issue comes up when you do somthing along the lines of

int x = 0;
for(x = 0;x < num; x++){}

When you are declaring your loop and you already initialize your variable, x you don't need to declare it a second time. So either do:

int x = 0;
for(; x < num; x++){}

Or

int x;
for(x = 0; x < num; x++){}

Upvotes: 1

Mahesh
Mahesh

Reputation: 34625

for(currentDirection; currentDirection <= endDirection; currentDirection++)
 // ^^^^^^^^^^^^^^^ Its saying about the above statement.

First statement should have an assignment, which is not happening in this case and is the reason for the warning. Make sure currentDirection is assigned to a valid value or it might have garbage and might later cause issues.

It is similar to when said -

 int i = 10 ;
 i ;   // This statement is valid but has no effect.

Upvotes: 9

ThiefMaster
ThiefMaster

Reputation: 318548

currentDirection; does nothing.

Replace your line with

for(; currentDirection <= endDirection; currentDirection++)

Or, in case you just forgot to initialize the variable:

for(currentDirection = 0; currentDirection <= endDirection; currentDirection++)

Upvotes: 37

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