假定time结构包含三个成员：hour、minute和second（都是int类型）。由用户读入从午夜开始的秒数total_sec，请计算出一个等价的时间结构，等价的时间用小时（0 ~23）、分钟（0 ~59）和秒（0 ~59）表示。
Enter total seconds：2590
Time：0:43:10

Enter total seconds：39802
Time：11:3:22

#include <stdio.h>

/* 宏定义 */
#define UINT32 unsigned int
#define UINT16 unsigned short
#define UINT8  unsigned char

#define FAILURE 1
#define SUCCESS 0

#define TOTAL_SECOND_PER_MINUTE 60
#define TOTAL_SECOND_PER_HOUR   3600

/* 数据结构定义 */
typedef struct time
{
    UINT8 ucHour;
    UINT8 ucMinute;
    UINT8 ucSecond;
}STRUCT_TIME;

STRUCT_TIME gstrTime;

/* 获取时间秒数 */
UINT32 getTotalSecond(UINT32 *pulTotalSecond)
{
    if(NULL == pulTotalSecond)
    {
        printf("para error !\n");

        return FAILURE;
    }

    printf("Plz input the ulTotalSecond:");
   
    while(1)
    {
        scanf("%u", pulTotalSecond);
        if(*pulTotalSecond < 0)
        {
            printf("Input error !\n");
        }
        else
        {
            break;
        }
    }

    return SUCCESS;
}

/* 转换并输出时间 */
UINT32 getTrueTime(UINT32 ulTotalSecond, STRUCT_TIME *pstrTime)
{
    if(NULL == pstrTime)
    {
        printf("para error !\n");

        return FAILURE;
    }

    pstrTime->ucHour   = ulTotalSecond/TOTAL_SECOND_PER_HOUR;
    pstrTime->ucMinute = (ulTotalSecond -(pstrTime->ucHour * TOTAL_SECOND_PER_HOUR))/TOTAL_SECOND_PER_MINUTE;
    pstrTime->ucSecond = ulTotalSecond%TOTAL_SECOND_PER_MINUTE;

    printf("Time: %u:%u:%u \n", pstrTime->ucHour, pstrTime->ucMinute, pstrTime->ucSecond);

    return SUCCESS;
}

int main(void)
{
    UINT32 ulTmp;
    UINT32 ulTotalSecond = 0;
    STRUCT_TIME *pstrTime = (STRUCT_TIME *)&gstrTime;
   
    ulTmp = getTotalSecond(&ulTotalSecond);
    if(ulTmp)
    {
        return FAILURE;
    }

    ulTmp = getTrueTime(ulTotalSecond, pstrTime);
    if(ulTmp)
    {
        return FAILURE;
    }

    return SUCCESS;
}

我觉得这么写比较正规一些，虽然有的分支可能是多余的，欢迎大家讨论