Variable parameter list

In C + + there is a function overload, in C there is a variable parameter list, the STDARG macro implementation is defined in the <stdarg.h> header file, there are 3 macros:va_start(va_list variable name , The last named argument before the ellipsis ) is used for initialization,va_arg(variable name of va_list , variable parameter type ) for removing variable parameters,va_end(VA _list variable name ) is used to indicate the end value, declaring a variable of type va_list, such as ARG, with va_list

#include <stdio.h> #include <stdarg.h>float average (int val,...) {    va_list arg;    int count;    float sum = 0;    Va_start (arg,val);    for (count = 0;count < val;count++)    {        sum + = Va_arg (Arg,int);    }    Va_end (ARG);    return sum/val;} averaging int main () {    printf ("%f\n", average (5,1,2,3,5,6));    return 0;}

Variable parameter list