求大佬们看看问题在哪啊

#include<stdio.h>
int main()
{
    int nSelection = -1;
    printf("\n------欢迎进入计费管理系统------\n");
    printf("\n");
    do {
        outputMenu();
        scanf("%d", nSelection);
    } while (nSelection != 0);
    return 0;
}
void outputMenu() {
    printf("1.添加卡\n");
    printf("2.查询卡\n");
    printf("3.上机\n");
    printf("4.下机\n");
    printf("5.充值\n");
    printf("6.退费\n");
    printf("7.统计查阅\n");
    printf("8.注销卡\n");
    printf("0.退出\n");
    printf("\n请选择菜单项（0~8）：\n");
}