#include<stdio.h>
#include<stdlib.h>
#include<string.h>
struct Car
{
    char maker[20];
    int price;
};
struct Citizen
{
    char* name;     //姓名
    int deposite;   //存款
    Car* car;//没车的时候用NULL来表示
};
 void buy(Citizen* owner)
{
    Car* car = (Car*)malloc(sizeof(Car));
    strcpy(car->maker, "Chevrolet");
        car->price = 10;
    owner->car = car;
    owner->deposite -= car->price;
   

}
void discard(Citizen* owner)
{
    free(owner->car);
    owner->car = NULL;
}
void sell(Citizen* owner, Citizen* other)
{
    Car* car = owner->car;
    car->price *= 0.5;
    other->car = car;
    owner->deposite += car->price;
    owner->car = NULL;
}
int main()
{ int i;
    struct    Citizen duxuan = { "duxuan",30,NULL };
    struct    Citizen laowu = { "laowu",50,NULL };
    buy(&duxuan);
    printf("我的车名为%s\n该车花费为%d\n我剩余的存款为%d\n",duxuan.car->maker,duxuan.car->price,duxuan.deposite);
    printf("1报废\n2出售\n");
    scanf("%d",i);
    if(i=1){
        discard(&duxuan);
    }
    else if(i=2){
        sell(&duxuan,&laowu);
    }
    return 0;

}

    scanf("%d",&i);
    if(i==1){
        discard(&duxuan);
    }
    else if(i==2){
        sell(&duxuan,&laowu);
    }

能帮我改下错吗？

不是已经改过来了吗？
就是不知道你的程序要做什么，所以运行完以后啥都不会输出

不好意思，我眼拙

scanf("%d",i);  改成 scanf("%d",&i);