7Seg Display through Shiftregister, Code optimization

Using Arduino Programming Questions
2

Create an array of output values.

int out[] = {B00000110, B01010011...};

then replace all of your code with:
digitalWrite(LATCH_PIN, LOW);
shiftOut(DATA_PIN, CLOCK_PIN, MSBFIRST, out[outputValue-1]);
digitalWrite(LATCH_PIN, HIGH);