27 lines
723 B
Plaintext
27 lines
723 B
Plaintext
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#!/bin/sh
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! eq $# 2 && printf "Usage: $0 [base] [exponent]\n" >/dev/stderr && exit 1
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! stris int "$1" && printf -- "%b: %b: Not an integer\n" "$0" "$1" >/dev/stderr && exit 1
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! stris int "$2" && printf -- "%b: %b: Not an integer\n" "$0" "$2" >/dev/stderr && exit 1
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base=$1
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exponent=$2
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result=1
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while gt $exponent 0; do
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result=$(multiply $result $base)
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exponent=$(-- $exponent)
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done
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if ! eq $result $(abs $result) && eq $base $(abs $base); then
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printf "$0: Result is unexpectedly negative, possible integer overflow\n" >/dev/stderr && exit 1
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elif eq $result 0 && ! eq $base 0; then
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printf "$0: Result is unexpectedly zero, possible integer overflow\n" >/dev/stderr && exit 1
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else
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printf "%b\n" $result
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fi
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exit 0
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