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POC++ compiler warning(?) when passing uninitialized local variable to function
 

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    <p>I'm very new to C++ so I'm hoping someone would shed some light. I came across several similar topics but I just need clarification.</p> <p>So it seems it's valid to pass a local string that has been declared but not initialized to a function. But why does compiler complain when you try it with int or float??</p> <p>Whether it's string, float, or int, memory address gets referenced when it is declared even tho it may be "garbage"</p> <pre><code>#include &lt;iostream&gt; using namespace std; void load(int); int main() { int salary; load(salary); return 0; } void load(int sal) { cout &lt;&lt; "your salary: " &lt;&lt; endl; cin &gt;&gt; sal; cout &lt;&lt; sal &lt;&lt; endl; } </code></pre> <p>If I declare int or float as global variable, it works as expected without any warnings. So then is it a better practice to declare variable in global space (I hope not)?</p> <p>So putting it in global, it works :</p> <pre><code>#include &lt;iostream&gt; using namespace std; int salary; void load(int); int main() { load(salary); return 0; } void load(int sal) { cout &lt;&lt; "your salary: " &lt;&lt; endl; cin &gt;&gt; sal; cout &lt;&lt; sal &lt;&lt; endl; } </code></pre> <p>ok, another example to show that uninitialized global variable works when passing to function as value : (going off of David's comment)</p> <pre><code>int foo; int returnit(int j) { cout &lt;&lt; "your salary"; cin &gt;&gt; j; return j; } int main() { int k = returnit(foo); cout &lt;&lt; k; return 0; } </code></pre> <p>anyways, lesson here is to initialize primitive data types before passing to functions.</p>
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    1. COSo what do you think this code does? Except compile error.
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    2. COyea, i know it compiles errors. But declaring as global variable without initializing can be passed to function. I'm trying to understand why that is.
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    3. COYou are incorrect, uninitialized global variables also cannot be passed by value to a function. The difference is just pure luck -- one happens to work and one happens not to work.
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      1. USDavid Schwartz
 

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