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POHow can I generate random int numbers within a set range (without duplicates!) within a class constructor?
 

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  1. POHow can I generate random int numbers within a set range (without duplicates!) within a class constructor?
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    <p>I am self-learning C++ from a text book and I have a problem to solve, outlined below.</p> <p>I have the following class structure:</p> <pre><code> #include &lt;iostream&gt; #include &lt;cstdio&gt; #include &lt;ctime&gt; using namespace std; class classroom{ char name[25]; int student_id; float grades[10]; float average; int num_tests; float letter_grade; public: void enter_name_id(void); void enter_grade(void); void average_grades(void); void letter_grades(void); void output_name_id_grade(void); classroom(); }; </code></pre> <p>And I have the following Constructor for the above class:</p> <pre><code> classroom::classroom(){ int i; srand((unsigned)time(0)); int random_integer=0; random_integer = (rand()%5) + (rand()%5); num_tests=0; average=0.0; for(i=0;i&lt;10;i++){ grades[i]=0.0; } for(i=0;i&lt;27;i++){ name[i]='-'; } cout&lt;&lt;"\n*****************Finished*****************"; } </code></pre> <p>There will be 3 students of this class structure declared in the <code>main</code>:</p> <pre><code>int main() { classroom students[3]; //and so... } </code></pre> <p>I need to generate a unique student ID for each student in the constructor within a range of values, say, 0 to 10.</p> <p>I have copied the following code snippet into the constructor. It generates my random number for me within the desired range:</p> <pre><code>srand((unsigned)time(0)); int random_integer=0; random_integer = (rand()%5) + (rand()%5); </code></pre> <p>The problem is that I need to get rid of any duplicates within the range of random numbers that are generated.</p>
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    1. USJamal
    1. USMr_leighman
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      1. POHow can I generate random int numbers within a set range (without duplicates!) within a class constructor?
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      1. VTUpMod
    1. COCorrection: int random_integer=0; should read int random_integer;
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      1. POHow can I generate random int numbers within a set range (without duplicates!) within a class constructor?
      1. USMr_leighman
    2. COWhy do you 1) use this sum of 2 random numbers (which is basically *not* giving you a random number in the desired range) 2) assume a random number can serve as an identifier ?
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      1. POHow can I generate random int numbers within a set range (without duplicates!) within a class constructor?
      1. USTibo
    3. COJust a little note, the class name is very misleading -- the object appears to be closer to a `student` than a `classroom`. You should consider naming your classes just as you would describe them -- in this case, they represent and contain data about a student -- so they should be named something like `Student`.
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      1. USjedwards
 

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