MQL5 compiler diagnostic
MQL5 array out of range error means an index is outside the valid interval from zero to ArraySize(array) minus one. Compiler code 218 catches determinable cases; runtime critical failures can still occur when the index depends on live data. Guard the index, loop with i < size, and check copied or calculated counts before reading.
Open the Coding Agent and choose MQL5 from the language menu.
void PrintValues(const double &values[])
{
int size=ArraySize(values);
for(int i=0;i<size;i++)
PrintFormat("values[%d]=%.5f",i,values[i]);
}
bool HasIndex(const double &values[],const int index)
{
return index>=0 && index<ArraySize(values);
}Also searched as: mql5 array out of range error fix; mql5 index out of range.
MetaEditor reports index out of array range when the source cannot satisfy the language or API contract at that location. Compile errors prevent creation of the EX5 program until they are resolved.
Start with the first error in the build output. A missing delimiter, declaration, or include can make later lines produce secondary messages that disappear after the root cause is fixed.
Compare the exact failing line with its declaration and the official reference. Keep the compiler line and column in the repair prompt or issue report.
Derive bounds from the array at the point of access. For copied series, use the returned count as the readable length. For OnCalculate, also keep rates_total, prev_calculated, and lookback requirements consistent.
Compile after each coherent edit. When the first diagnostic moves or disappears, re-read the remaining list instead of applying stale fixes from the previous build.
The loop uses the exclusive upper bound and the helper validates both negative and oversized indexes. Series direction changes meaning, not the valid index interval.
A clean compile or a cleared error code does not prove strategy logic, broker compatibility, backtest quality, or live-trading safety. Reproduce the result in the target MetaTrader 5 terminal and account environment.
void PrintValues(const double &values[])
{
int size=ArraySize(values);
for(int i=0;i<size;i++)
PrintFormat("values[%d]=%.5f",i,values[i]);
}
bool HasIndex(const double &values[],const int index)
{
return index>=0 && index<ArraySize(values);
}Pineify can generate or revise MQL5 source and use MQL5 compilation diagnostics during the coding workflow. Keep the exact error, source location, program type, and intended behavior in the request so the change remains reviewable.
Open MQL5 Coding AgentPineify does not run your broker terminal, Strategy Tester, market data, or live orders. Validate the final program in your own MetaTrader 5 environment.
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Record the message, code 218, file, line, and column from MetaEditor 5.
Open the first failing line and inspect the declaration, delimiters, include dependencies, and nearby syntax before touching later messages.
Derive bounds from the array at the point of access. For copied series, use the returned count as the readable length. For OnCalculate, also keep rates_total, prev_calculated, and lookback requirements consistent.
Press F7, confirm the compiler result, then run the EA, indicator, or script in the appropriate MetaTrader 5 test environment.
The official MQL5 compilation table defines code 218 as "Index out of array range."
No. Fix the first credible root error and compile again. One malformed statement can create several downstream diagnostics.
No. Compilation validates source and type contracts. Runtime behavior, order handling, strategy logic, and broker compatibility require separate tests.
Last verified against the linked official references on . Compile and test the final source in the MetaTrader 5 build, broker, symbol, and account environment you plan to use.
Provide the exact diagnostic and intended behavior, inspect the generated change, compile it, and verify it in your MT5 test environment.
Open MQL5 Coding Agent