Re: 100 Random Single Variable Linear Equations

Mike Sanders <porkchop@invalid.foo> wrote:

# outputs 100 random single variable linear equations in the form: ax+b=c

now randomly creates up to 2 instances of 'x' per equation & 3 random forms...

ax op1 b = c
ax op1 bx = c
ax op1 b op2 x = c

(really more than 3 if there's a leading negtive)

and unless there's something out of whack, i'm using this version, because
algebra can melt my brain as it increases in complexity...

BEGIN {
    # seed random number generator
    if (SEED+0 != SEED) SEED = 1; srand(SEED)

    # keep generating until we have exactly 100 unique equations
    do {
        a = rnd(1, 20)                  # random value for coefficient x
        b = rnd(1, 99)                  # random value for b constant
        c = rnd(1, 99)                  # random value for c constant
        n = (rnd(1, 2) == 1) ? "-" : "" # random negative for coefficient x
        f = rnd(1, 3)                   # random equation form
        op1 = rop()                     # random operator

        if (f == 1) {
            # simple equation: ax op1 b = c
            e = sprintf("%s%dx %s %d = %d", n, a, op1, b, c)
        } else if (f == 2) {
            # medium complexity: ax op1 bx = c
            b2  = rnd(1, 20) # new/different coefficient for 2nd x
            op2 = rop()      # 2nd random operator
            e   = sprintf("%s%dx %s %dx = %d", n, a, op1, b2, op2, c)
        } else if (f == 3) {
            # more complex: ax op1 b op2 x = c
            op2 = rop() # 2nd random operator
            e   = sprintf("%s%dx %s %d %s x = %d", n, a, op1, b, op2, c)
        }

        # store equation in array if it doesn't already exist
        if (!(e in equ)) {
            equ[e] = 1 # mark element as reserved
            u++        # increment u for each unique equation
        }

    } while (u < 100)

    # print seed & equations
    printf("SEED: %d\n\n", SEED)
    for (j in equ) printf("%03d. %s\n", ++i, j)
}

function rop() { return substr("+-*/", rnd(1, 4), 1) }

function rnd(min, max) { return int(rand() * (max - min + 1)) + min }

# eof

--
:wq
Mike Sanders