数据通过引用而不是值

我正在尝试制作一个具有菜单的程序,并且可以选择设置"当前"日期.我可以定义日期,它将一直保持到程序关闭.我有另一种方法来获取日期,通过询问用户链接一个人的日期,问题是它不会继续主菜单上的主要数据.它只是人员结构上.date的数据,我想我解释得很好.我尝试了很多方法,如果有人可以帮我解决的话,我真的无法理解...

typeData readData() {    
    int val;
    typeData data;
    do {
        printf("Day: ");
        data.day = readInteger(MIN_DAYS, MAX_DAYS);
        printf("Month: ");
        data.month = readInteger(MIN_MONTH, MAX_MONTH);
        printf("Year: ");
        data.year = readInteger(MIN_YEAR, MAX_YEAR);
        val = validateData(data);
        if(val == 0) {
            printf("The data is not valid.\n");
        }
    } while (val == 0);
    return data;
}

我想我需要通过引用得到它,但我已经尝试了一段时间而且不能这样做.感谢大家.

虽然它是合法的C,但是按值传递结构并返回它们通常不是最好的方法.考虑:

void
readData(typeData *data)
{

    int val;

    do {
        printf("Day: ");
        data->day = readInteger(MIN_DAYS, MAX_DAYS);

        printf("Month: ");
        data->month = readInteger(MIN_MONTH, MAX_MONTH);

        printf("Year: ");
        data->year = readInteger(MIN_YEAR, MAX_YEAR);

        val = validateData(data);
        if (val == 0) {
            printf("The data is not valid.\n");
        }
    } while (val == 0);
}

更新:

以下是主程序示例以及示例更改validateData:

int
validateData(typeData *data)
{
    int data_valid = 1;

    // check for error
    // this is whatever checks you already do ...
    if (data->... != ...)
        data_valid = 0;

    return data_valid;
}

int
main(int argc,char **argv)
{
    typeData main_data;

    readData(&main_data);

    // do something useful with the data [or transform it, etc]
    processData(&main_data);

    // print some results
    printData(&main_data);

    return 0;
}

更新#2:

这是基于您最新示例的修改后的[部分]程序.我不得不猜测整个组织,但至少它有以下必要的变化menuPrincipal:

int
validateData(typeData *data)
{
    int data_valid = 1;

    // check for error
    // this is whatever checks you already do ...
    if (data->... != ...)
        data_valid = 0;

    return data_valid;
}

char
menuPrincipal(typeDate *date)
{
    char option;

    if (date->day == 0 && date->month == 0 && data->year == 0) {
        printf("Date not set yet.\n");
    }
    else {
        printf("Date: %d/%d/%d", date->day, date->month, date->year);
    }

    // more stuff

    return option;
}

int
main(int argc,char **argv)
{
    typeData main_data;
    char option;

    while (1) {
        readData(&main_data);

        option = menuPrincipal(&main_data);

        switch (option) {
        case 'a':  // do something
            break;

        case 'b':  // do something else
            break;

        default:
            printf("unknown option: '%c'\n",option);
            break;
        }
    }

    return 0;
}

更新#3:

根据您的最新评论,我想我看到您遇到的问题.我已经使用了您最新的代码段并进行了更新:

// your original code -- this no longer works because readData is now void
if (data->ano == 0 && data->mes == 0 && data->dia == 0) {
    Blah[*Bleh].date = readData(*data);
}

// one possibility -- but it does _not_ update "data"
if (data->ano == 0 && data->mes == 0 && data->dia == 0) {
    readData(&Blah[*Bleh].date);
}

// this is more likely what you want -- it updates _both_:
if (data->ano == 0 && data->mes == 0 && data->dia == 0) {
    readData(data);
    Blah[*Bleh].date = *data;
}