Martuza's blog

Change the value 0 to 1 or 1 to 0 of a flag variable
By Martuza, 12 years ago, In English

Sometimes we use flag variables for indicating some operations. and we need to change the value of flag 0 to 1 or 1 to 0. we use this statements 

bool flag = 1;
if(flag == 1) flag = 0;
else flag = 1;

But how I get same result not using these statements? Have any mathematical calculation for this ? Please anyone help me.

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12 years ago, # |
  Vote: I like it +16 Vote: I do not like it 
bool new_flag = !flag;

int new_flag = 1 - flag;
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12 years ago, # |
← Rev. 2   Vote: I like it +14 Vote: I do not like it 
bool flag = 1;
flag ^= 1

^ xor operation.

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    12 years ago, # ^ |
    ← Rev. 2   Vote: I like it -9 Vote: I do not like it

    Sorry I understand it.

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      12 years ago, # ^ |
        Vote: I like it +1 Vote: I do not like it

      It will work anyway. Let's see an example. If flag is equal to true, then that line will work as flag = 1 ^ 1 = 0, else flag = 0 ^ 1 = 1.

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      12 years ago, # ^ |
        Vote: I like it 0 Vote: I do not like it

      xor does exactly the same

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12 years ago, # |
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bool flag = true;
flag = !flag;
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12 years ago, # |
  Vote: I like it 0 Vote: I do not like it

flag ^= 1;

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