The function of variable length parameter

A small example of a function with variable length parameters in C language:

#include <stdio.h>
#include <stdarg.h>
#include <assert.h>
static int pp;
void func1()
{
    static int pp1;
    printf("hello world\n");
}

void tiny_printf(char *format, ...)
{
    int i;
    va_list ap;
    va_start(ap, format);
    for (i = 0; format[i] != ‘\0‘; ++i)
    {
        switch (format[i])
        {
        case ‘s‘:
            printf("%s ", va_arg(ap, char*));
            break;
        case ‘d‘:
            printf("%d ", va_arg(ap, int));
            break;
        default:
            assert(0);
        }
    }
    va_end(ap);
    putchar(‘\n‘);
}

int main(void)
{
    char *str = "abc";
    tiny_printf("sdd", "hello", 3, 5);
    return 0;
}

In line 14th, declare the variable AP of type va_list. The va_list type is defined like this:

typedef char *va_list;
In line 15th, Va_start (AP, format) means "point the pointer ap to the next position in parameter format."
Va_arg () Set the AP and parameter types so that the parameters of the variable-length section can be removed in the book order.
The 30th line of Va_end () is just a decoration.

The function of variable length parameter