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POC Array change causing variable modification
 

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  1. POC Array change causing variable modification
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    <p>I am trying to modify a value in an array using the C programming language and I seem to be hitting a blank wall with this seemingly easy operation. Please see code snippet below:</p> <pre><code>while(1) { printf("Current prime candidate is %i\n",nextPrimeCandidate); int innerSieve;//=2; int currentPrimeCandidate=0; for (innerSieve=2;innerSieve&lt;SIEVELIMIT;innerSieve++) { currentPrimeCandidate = nextPrimeCandidate * innerSieve; //printf("Inner Sieve is b4 funny place %i,%i\n",innerSieve,currentPrimeCandidate); //initArray[currentPrimeCandidate]=5; //VERY UNIQUE LINE myArray[currentPrimeCandidate] = 0; //printf("Inner Sieve after funny place is %i,%i \n",innerSieve,currentPrimeCandidate); } nextPrimeCandidate=getNextPrimeCandidate(myArray,++nextPrimeCandidate); if ((nextPrimeCandidate^2) &gt; SIEVELIMIT ) break; } </code></pre> <p>The problem is with the line highlighted with the <code>VERY UNIQUE LINE</code> comment. For some reason, when the innerSieve variable reaches 33 and gets to that line, it sets the contents of the innerSieve variable to the value of that line ( which currently is 0) and basically forces the loop into an infinite loop( the <code>SIEVELIMIT</code> variable is set at 50). It seems that there is some funny stuff going on in the registers when I checked using the Eclipse Debug facility but I am not too sure what I should be looking for.</p> <p>If you need the whole code listing, this can be provided.( with a particular variable which is not yet initialised in the code being initialised at the precise point that the innerSieve variable hits 32)</p> <p>Any help will be greatly appreciated.</p>
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    1. USKris Ogirri
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    1. COAnd what does `if ((nextPrimeCandidate^2) > SIEVELIMIT ) break;` means?
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      1. USruslik
    2. COI apparently was trying to check if `nextPrimeCandidate` raised to the power of 2 was greater than `SIEVELIMIT` but after reading Adam Rosenfields answer below, I should really forget my JAVA experience when dealing with C
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