34 lines
695 B
Bash
34 lines
695 B
Bash
#!/usr/bin/env bash
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# check if a command-line argument was provided
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if [ -z "$1" ]
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then
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echo "Error: invalid input"
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exit 1
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fi
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square=$1
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# check if the square number is valid
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if [[ "$square" != "total" ]] && (( square < 1 || square > 64 ))
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then
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echo "Error: invalid input"
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exit 1
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fi
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if [[ $square == "total" ]]
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then
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total_grains=0
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for ((square=1; square<=64; square++))
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do
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grains_on_square=$(echo "2^($square-1)" | bc)
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# use floating point arithmetic (bc)
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total_grains=$(echo "$total_grains + $grains_on_square" | bc)
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done
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echo $total_grains
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else
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grains_on_square=$(echo "2^($square-1)" | bc)
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echo $grains_on_square
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fi
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