Converting a 15-character all-numeric string from ASCII to 2-3 unsigned longs

Projects General Guidance
13

Here is a deliberately clumsy code, to show the principles, but doing the job.

char inputArray[] = "123456789098765";//Test sample
long v1, v2, v3;


int makenum(char a)
{
  return ( a - 48 );
}
void setup() {
  Serial.begin(115200);
  Serial.println("v1");
  v1 = makenum(inputArray[4]);//LSB var1
  Serial.println(v1);
  v1 += 10 * makenum(inputArray[3]);
  Serial.println(v1);
  v1 += 100 * makenum(inputArray[2]);
  Serial.println(v1);
  v1 += 1000 * makenum(inputArray[1]);
  Serial.println(v1);
  v1 += 10000L * makenum(inputArray[0]);/MSB var1
  Serial.println(v1);
  Serial.println("v2");
  v2 = makenum(inputArray[9]);
  Serial.println(v2);
  v2 += 10 * makenum(inputArray[8]);
  Serial.println(v2);
  v2 += 100 * makenum(inputArray[7]);
  Serial.println(v2);
  v2 += 1000 * makenum(inputArray[6]);
  Serial.println(v2);
  v2 += 10000L * makenum(inputArray[5]);
  Serial.println(v2);
  Serial.println("v3");
  v3 = makenum(inputArray[14]);
  Serial.println(v3);
  v3 += 10 * makenum(inputArray[13]);
  Serial.println(v3);
  v3 += 100 * makenum(inputArray[12]);
  Serial.println(v3);
  v3 += 1000 * makenum(inputArray[11]);
  Serial.println(v3);
  v3 += 10000L * makenum(inputArray[10]);
  Serial.println(v3);
}

void loop() {
  // put your main code here, to run repeatedly:

}