#/***********************************************************
#    seqsrch.rb -- 逐次探索
#***********************************************************/
NOT_FOUND = (-1)

def seqsrch1(x, a,  m,  n)
    while (m <= n && a[m] != x); m += 1; end
    if (m <= n); return m; end
    return NOT_FOUND
end

def seqsrch2(x, a,  m,  n)
    if (m > n); return NOT_FOUND; end
    a[n + 1] = x;  # 番人 
    while (a[m] != x); m += 1; end
    if (m <= n); return m; end
    return NOT_FOUND
end

def seqsrch3(x, a,  m,  n)
    if (m > n); return NOT_FOUND; end
    t = a[n];  a[n] = x;  # 番人 
    while (a[m] != x); m += 1; end
    a[n] = t
    if (m < n); return m; end
    if (x == t); return n; end
    return NOT_FOUND
end

#********************************************************

N = 20

a = []

printf("***** 逐次探索デモンストレーション *****\n")
srand
for i in 0...N
    a[i] = (100 * rand).to_i
end
printf("  i : ")
for i in 0...N; printf(" %2d", i); end
printf("\n")
printf("a[i]: ")
for i in 0...N; printf(" %2d", a[i]); end
printf("\n")

printf("\n何を探しますか? ")
x = gets.to_i

printf("seqsrch1: ")
i = seqsrch1(x, a, 0, N - 1)
if (i != NOT_FOUND); printf("i = %d\n", i)
else;                printf("見つかりません\n"); end

printf("seqsrch2: ")
i = seqsrch2(x, a, 0, N - 1)
if (i != NOT_FOUND); printf("i = %d\n", i)
else;                printf("見つかりません\n"); end

printf("seqsrch3: ")
i = seqsrch3(x, a, 0, N - 1)
if (i != NOT_FOUND); printf("i = %d\n", i)
else;                printf("見つかりません\n"); end

exit 0