c - 警告 : format '%d' expects argument of type 'int *' , 但参数 2 的类型为 'int'

Question

这是为了我进入 C 类，我不明白为什么会出现此错误:

while (scanf ("%d", (int)ph[i].vi.temperature) < 0) { 
warning: format '%d' expects argument of type 'int *', but argument 2 has type 'int'

代码:

struct vitalInformation {
    float temperature;
    unsigned int systolicPressure;
    unsigned int diastolicPressure;
};

struct activityInformation {
    unsigned int stepCount;
    unsigned int sleepHours;
};

union patientHealth{
    struct vitalInformation vi;
    struct activityInformation ai;
} ph[100]; 

int i = 0;

int menu(){
    int option;

    printf ("Please enter the number for the desired action (1, 2, 3):\n");
    printf ("1 - Enter some patient vital information\n");
    printf ("2 - Enter some patient activity information\n");
    printf ("3 - Print summary information on the patient information and exit the program\n");

    scanf ("%d", &option);

    while (scanf("%d", &option) || option<1 || option>3) {
        printf ("Please enter 1, 2, or 3\n\n");
        printf ("Please enter the number for the desired action (1, 2, 3):\n");
        printf ("1 - Enter some patient vital information\n");
        printf ("2 - Enter some patient activity information\n)");
        printf ("3 - Print summary information on the patient information and exit the program\n");

        fflush (stdin);
        scanf ("%d", &option);

    }

    return option;
}

void patientVitalInfo(int *countP, float *minT, float *maxT, int *minS, int *maxS, int *minD, int *maxD) {
    printf ("Enter the temperature: ");
    scanf ("%f", &ph[i].vi.temperature);

    while (scanf ("%d", (int)ph[i].vi.temperature) < 0) {
        printf ("Please enter an integral unsigned number\n");
        printf ("Enter the temperature: ");

        fflush (stdin);
        scanf ("%f", &ph[i].vi.temperature);
    }
}

Answer 1

报错来自你的线路

while (scanf ("%d", (int)ph[i].vi.temperature) < 0) {

它会将你从 ph[i].vi.temperature(在本例中为 float)中得到的任何内容转换为 int ，而 scanf 需要一个指向 int 的指针。

现在，在您的情况下，您似乎需要将温度作为 int，而ph[i].vi.温度持有一个float，所以你宁愿使用另一个int变量，比如说

int itemp;
scanf ("%d", &itemp);

用于输入然后

ph[i].vi.temperature = (float) itemp;

用于类型转换。或者，您可以简单地 scanf ("%f", &ph[i].vi.temperature); 然后保留整数部分。我不知道您的需求，也不知道您的代码背后的逻辑。

注意:我不确定您是否以符合您需要的方式使用 scanf 的返回值。在您的情况下，scanf 可以返回 0、1 或 EOF。