C编程基础-基础篇 10

#include <stdio.h>
#include <string.h>

typedef struct Books {
    char title[50];
    char author[50];
    char subject[100];
    int book_id;
} Book;

int main() {
    Book  book;
    strcpy(book.title, "C 教程");
    printf( "书标题 : %s\n", book.title);

    return 0;
}

书标题 : C 教程

#include <stdio.h>
#include <stdarg.h>

double average(int num, ...) {
    va_list valist;
    double sum = 0.0;
    int i;

    va_start(valist, num);
    for (int j = 0; j < num; ++j) {
        sum += va_arg(valist, int);
    }
    va_end(valist);

    return sum/num;
}

int main() {
    printf("average of 2, 3, 4, 5 = %f\n", average(4, 2,3,4,5));
    return 0;
}

average of 2, 3, 4, 5 = 3.500000