#include<stdio.h>
int main (void)
{
    unsigned int un = 3000000000;//int 为32位.
    short end = 200;
    long big = 65537;
    long long verybig = 12345678908642;
    printf("un=%u and not %d\n",un,un);
    printf("end = %hd an %d\n",end,end); 
    printf("big = %ld an not %hd\n",big,big);
    printf("verybig=%lld and not %ld\n",verybig,verybig);
    return 0;
}

我的编译器是Codeblocks支持C99，不知道为什么会警告。

long long verybig = 12345678908642;
报警的是这句吧，默认的常整数是long型的。加后缀LL告诉编译器它是64位整型。即
long long verybig = 12345678908642LL;