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    <h2>About access violation:</h2> <blockquote> <p><strong>Access Violation</strong> is generally an attempt to access memory that the CPU cannot physically address.</p> </blockquote> <h2>Common causes:</h2> <blockquote> <p>Dereferencing NULL pointers . (<strong>THIS IS YOUR CASE see picture</strong>). You want to access to 0x000(NULL) location</p> <p>Attempting to access memory the program does not have rights to (such as kernel structures in process context) </p> <p>Attempting to access a nonexistent memory address (outside process's address space)</p> <p>Attempting to write read-only memory (such as code segment)</p> </blockquote> <p><strong>More :<a href="http://en.wikipedia.org/wiki/Segmentation_fault" rel="nofollow">more here in wikipedia</a></strong></p> <h2>How you should allocate (using your structure):</h2> <p>First You should allocate memory;<em>And dont forget you should write its free function,too</em></p> <p>Simple allocation would be such:</p> <pre><code> //instead I advice PCurrentData notation CurrentData AllCurrentData=malloc(NumProduct* sizeof *CurrentData); //memset so we can then check it with null memset(AllCurrentData,0,NumProduct* sizeof *CurrentData); int i,y; for(i=0;i&lt;NumProduct;i++){ //Noncontiguous allocation.Suits to string allocation,cause string lens differs AllCurrentData[i].data=malloc(COLUMNS*sizeof(char**)); memset(AllCurrentData[i].data,0,COLUMNS*sizeof(char**)); for(j=0;j&lt;COLUMNS;j++){ //this is just example //probably you want to allocate null terminating string int size=strlen(your_null_terminating_string)+1;//+1 for adding null,too AllCurrentData[i].data[j]=malloc(size*sizeof(char)); memcpy(AllCurrentData[i].data[j],your_null_terminating_string,size); } } </code></pre> <h2>Additionaly, What else is wrong in your code and proper way</h2> <p>Plus you are doing wrong. Looking at your structure you hold <code>char**</code>.But you try to access it with <code>2D [][]</code> array. <strong>Why we can not? Cause there is no guarantee that</strong> <code>char**</code> <strong>reference to continguous allocation, or only it done ,by manually, the way that compiler can access to it with [][]</strong>. Plus for <code>char**</code> mostly allocation done with noncontinguous way.cause strings len differs</p> <p>So Note these:</p> <p><code>char**</code> <strong>is not equal to</strong> 2D array <code>char v[][] array</code>. So doing <code>AllCurrentData[i].data[j][k]</code> is <strong>wrong</strong> to address <code>char**</code>.</p> <p>only <code>char*</code> can be equally treated as one dimensional <code>char v[]</code> array. <code>char[]</code> decay to <code>char*</code></p> <p>So accessing should be done this way:</p> <pre><code>#define NULL 0 if(AllCurrentData[i]!=NULL &amp;&amp; AllCurrentData[i].data[j]!=NULL){ char* str=AllCurrentData[i].data[j]; if(str!=NULL) while (str[k]!='\0'){ printf("%c ",str[k]);++k; } } /*or while (*str){ printf("%c ",*str);++str; } */ /*but actualy you can print null terminating string directly (assuming you wanted this) if(str!=NULL) printf("%s",str); */ </code></pre> <p><a href="http://www.lysator.liu.se/c/c-faq/c-2.html" rel="nofollow">more to learn about arrays and pointers</a></p>
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    1. CO+1 `char**` does *not* decay from a 2D array. It is a pointer to a pointer; period. A 2D-array `char var[N][M]` decays (and I *hate* that word) to a `char (*)[M]`
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