Help me with C

Question

Does somebody know how I can get a number from user and reverse it?for example:45 chances to 54

Answer 1

let `n` be integer input. and `rev` be the integer initialized to 0.

while n! =0
rev *= 10
rev += n%10
n/=10

return rev

what this loop does is :
it multiplies the `rev` by 10 and stores result back into `rev`.
then adds the last digit (retrieved by mod division n%10) to `rev`.
next, it removes last digit of input number by using n/=10.
all this while n! =0.

example :
n = 45
rev = 0

in while, check n! =0 , this is true so execute loop body.
rev = 0 *10 = 0
rev = 0 + 45%10 = 0 + 5 = 5
n = 45/ 10 = 4
so after first iteration `rev` is 5 and `n` is 4

next iteration - check while, n! =0. true so execute loop body.

rev = 5*10 = 50
rev = 50 + (4%10) = 50 +4 = 54
n = 4/10 = 0

now `rev` is 54 and n = 0.

check while, n! =0 is false. loop body won't execute.

return value of `rev` which is 54

Try to code this logic as C function. If something doesn't work , ask here.

Answer 2

Don't store it as a number. Store it as a string and reverse the string.