35 lines
1.4 KiB
MQL5
35 lines
1.4 KiB
MQL5
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//+------------------------------------------------------------------+
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//| VariableScopes.mq5 |
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//| Copyright 2021, MetaQuotes Ltd. |
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//| https://www.mql5.com |
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//+------------------------------------------------------------------+
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#property copyright "Copyright 2021, MetaQuotes Ltd."
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#property link "https://www.mql5.com"
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#property version "1.00"
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// global variables
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int i, j, k; // i/j are 0s, k is unknown (unused and eliminated by compiler)
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int m = 1; // m = 1
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int n = i + m; // n = 1
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//+------------------------------------------------------------------+
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//| Script program start function |
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//+------------------------------------------------------------------+
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void OnStart()
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{
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// local variables
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int x, y, z;
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int k = m; // warning: declaration of 'k' hides global variable
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int j = j; // warning: declaration of 'j' hides global variable
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// use variables in assignment instructions
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x = n; // ok, 1
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z = y; // warning: possible use of uninitialized variable 'y'
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j = 10; // change local j, global j is still 0
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}
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// compilation error
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// int bad = x; // 'x' - undeclared identifier
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//+------------------------------------------------------------------+
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