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POC style strings, Pointers, arrays
 

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    <p>I'm having trouble understanding what a C-style string is. Happy early New Year</p> <p>What I know: A pointer holds a memory address. Dereferencing the pointer will give you the data at that memory location.</p> <pre><code>int x = 50; int* ptr = &amp;x; //pointer to an integer, holds memory address of x cout &lt;&lt; "&amp;x: " &lt;&lt; &amp;x &lt;&lt; endl; //these two lines give the same output as expected cout &lt;&lt; "ptr: " &lt;&lt; ptr &lt;&lt; endl; cout &lt;&lt; "*ptr: " &lt;&lt; dec &lt;&lt; (*ptr) &lt;&lt; endl; //prints out decimal number 50 //added dec, so the program doesnt //continue to printout hexidecimal numbers like it did for the //the memory addresses above cout &lt;&lt; "&amp;ptr: " &lt;&lt; &amp;ptr &lt;&lt; endl; //shows that a pointer, like any variable, //has its own memory address </code></pre> <p>Now to what I don't understand (using what's above as the source for my confusion): There are multiple ways to declare strings. I'm learning C++, but you can also use C-style strings (good to understand, although inferior to C++ strings)</p> <h3>C++:</h3> <pre><code>string intro = "Hello world!"; //the compiler will automatically add a null character, \0, so you don't have to //worry about declaring an array and putting a line into it that is bigger than //it can hold. </code></pre> <h3>C-style:</h3> <pre><code>char version1[7] = {'H','i',' ','y','o','u','\0'}; char version2[] = "Hi you"; //using quotes, don't need null character? added for you? char* version3 = "Hi you"; </code></pre> <p>Version3 is where I'm having trouble. Here, there is a pointer to a char. I know that an array name is a pointer to the first element in an array.</p> <pre><code>cout &lt;&lt; " &amp;version3: " &lt;&lt; &amp;version3 &lt;&lt; endl; //prints out location of 'H' cout &lt;&lt; " *version3: " &lt;&lt; *version3 &lt;&lt; endl; //prints out 'H' cout &lt;&lt; " version3: " &lt;&lt; version3 &lt;&lt; endl; //prints out the whole string up to //automatically inserted \0 </code></pre> <p>Before, in the section "what I knew," printing out the name of a pointer would print out the address that it held. Here, printing out the name of a pointer prints out the whole string. Do the double quotes around "Hi you" somehow tell the program: "hey I know you are a pointer, and you are initialized to the location of 'H', but because I see these double quotes, skip forward 1 byte in memory location and printout everything you see until you reach a \0" (1 byte movement because char's are 1 byte large). </p> <p>How is it that printing out a pointer prints out a string? Before printing out a pointer name printed out the memory address it was initialized to.</p> <p>Edit: Does <code>cout &lt;&lt; &amp;version3</code> print out the location of 'H' or the location of the pointer, <code>version3</code>, which holds the memory address of 'H'?</p>
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    1. USJonathan Leffler
    1. USDWade64
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    1. CORelated: see my answer to http://stackoverflow.com/questions/20794832/pointers-and-strings-c/20794936#20794936
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      1. USAndrey Mishchenko
    2. CO"Happy early New Year" thrown in there is kind of random. lol
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      1. USFiddling Bits
    3. COI'd say that calling C strings "inferior" to C++ strings is a little strong, especially considering that the one is (typically) implemented in terms of the other.
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      1. USAndrey Mishchenko
 

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