C/C++ varargs

#include <stdarg.h>

// Java的可变参数：int...
// C++的可变参数写法：...
void sum(int count, ...) {
    va_list vp;

    va_start(vp, count);  // 获取参数列表的指针

    for (int i = 0; i < count; ++i) { // 依次获取每个参数
        int r = va_arg(vp, int);
        LOGI("%d", r)
    }

    va_end(vp);  // 结束参数列表的处理
}

int main() {

    sum(3, 7, 8, 9);

    return 0;
}

Compared with Java, C/C++'s variable parameters are a bit more complicated to use. When defining parameters on a method, directly use ... to represent variable parameters.

How to use it in the method? Use va_start to get the pointer of the parameter list, and then use va_arg to get the value of the corresponding parameter. After getting it, you need va_end to close the pointer.

In java, if the array or collection crosses the boundary, an exception will be thrown, but C/C++ will not, and the system value (garbled characters) will be printed out, so when using pointers in C/C++, it is necessary to operate the pointer accurately and correctly, so as not to appear unexpected error