Functions with variable-length param lists.
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HI everyone. Could someone explain to someone else (ie me) how I can declare a function that gets a list of parameters which size is variable (like printf() or lie a function that would calculate the average of its parameters e.g).
Thanks for your help.
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You can do it by declaring a function thus;
int Average (int iStart, ...);
So...
int Average (int iStart, ...);
So...
#include <stdarg.h>#include <stdio.h>int Average (int iStart, ...);void main(){ printf("Average is: %d\n", Average(10,11,12,13,14,15,16,-1);}int Average(int iStart, ...){ int i = iStart; int iSum = 0; int iCount = 0; va_list oArgs; va_start(oArgs, iStart); while (i != -1) { iSum += i; iCount++; i = va_arg(oArgs, int); } va_end(oArgs); return (iSum ? (iSum / iCount) : 0);}
How would you take these parameters and pass them to printf, sprintf, or fprintf?
as in:
int Average (int iStart, ...);
how would you go about doing:
int Average (int iStart, ...)
{
fprintf(someFile, I don''t know the rest
}
also, isn''t iStart supposed to be a pointer?
as in:
int Average (int iStart, ...);
how would you go about doing:
int Average (int iStart, ...)
{
fprintf(someFile, I don''t know the rest
}
also, isn''t iStart supposed to be a pointer?
Check out vsprintf for the va_args version of sprintf.
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