What is causing error in first function which seemingly looks similar to second function?

Below functions are giving different results. What's the supposed difference between them that is causing different outputs. e.g n=30 and k=417219134 are giving output 0 and 1 respectively.

Function 1(Wrong):

int kthGrammar(int n, int k) {
if (n==1){
    return 0;
}
int parent_node = kthGrammar(n-1, ceil(float(k)/2));
int isKodd = k%2;
if (isKodd){
    return parent_node;}
else{
    return parent_node==0?1:0;}
}

Function 2(Right):

int kthGrammar(int n, int k){
if (n==1){
    return 0;
}
int isKodd = k%2;
if (isKodd){
    return kthGrammar(n-1, (k+1)/2);}
else{
    return (kthGrammar(n-1, k/2)==0?1:0);}
}