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

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4

Can't you use a for loop:
l = string length.
place=1
for (i=0;i<5; i++{
unsigned_long_intege1 += (ascii_string[(l-1)-i] - 48)* place;
place *= 10;
}
etc. for the other 2 longs?