이것이 c언어다. 13장 시계

처음 시간 입력후, 진행된 시간을 분단위로 입력하여, 얼마나 지났는지 계산하기.

#include <stdio.h>

int gHour;

int gMinute;

int gDay;

void setTime(int m);

void showTime(void);

int main(void)

{

    int nMoveTime;

    printf("enter primary time : ");

    scanf("%d %d",&gHour,&gMinute);

    fflush(stdin);

    printf("seted time : ");

    showTime();

    printf("enter a moved time(minute) : ");

    scanf("%d",&nMoveTime);

    setTime(nMoveTime);

    printf("moved time : ");

    showTime();

    return 0;

}

void showTime(void)

{

    char* ap;

    if(gHour>12){

        ap = "PM";

        gHour = gHour-12;}

    else

        ap = "AM";

    printf("%dDays %d:%d(%s)\n",gDay,gHour, gMinute,ap);

}

void setTime(int m)

{

    int i;

    gMinute = gMinute + m;

    while(gMinute > 60)

    {

        gMinute = gMinute - 60;

        gHour++;

    }

    while(gHour > 24)

    {

        gHour = gHour - 24;

        gDay++;

    }

}