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cembeddedvariable-assignment

Multiple assignment in one line

I just come across the statement in embedded c (dsPIC33)

sample1 = sample2 = 0;

Would this mean

sample1 = 0;

sample2 = 0;

Why do they type it this way? Is this good or bad coding?

Solution

  • Remember that assignment is done right to left, and that they are normal expressions. So from the compilers perspective the line

    sample1 = sample2 = 0;

    is the same as

    sample1 = (sample2 = 0);

    which is the same as

    sample2 = 0;
sample1 = sample2;

    That is, sample2 is assigned zero, then sample1 is assigned the value of sample2. In practice the same as assigning both to zero as you guessed.