adding or subtracting an hour, rtc stuff

Projects Programming
10

Here is one way to do it:

int hrOn, minOn, secOn, hrOff, minOff, secOff;

int i = 0; // you will need to make a loop later

// copy the numbers
hrOn   = pumpOnTime[i][0];
minOn  = pumpOnTime[i][1];
secOn  = pumpOnTime[i][2];
hrOff  = pumpOnTime[i][0];
minOff = pumpOnTime[i][1];
secOff = pumpOnTime[i][2];

// do arithmetic for the "on" time
hrOn = hrOn - 1; // move time to one hour earlier
if (hrOn < 0) {
  // in case our subtraction came out negative
  hrOn = hrOn + 24;
}

// do arithmetic for the "off" time
minOff = minOff + 30;
if (minOff >= 60) {
  // sixty minutes make one hour
  minOff = minOff - 60;
  hrOff = hrOff + 1;
}
if (hrOff >= 24) {
  // in case we went past midnight
  hrOff = hrOff - 24;
}