[Tawa]

I'm not sure if this is what you want, but give it a try:

#include <stdio.h>

int main(){
    int i;

    do{
        printf("Input Number: ");
        scanf("%d", &i);
    }while(i < 0);

    if(fork()==0){
        int j;
        int fibn=0;
        int fibnminus1=0;
        int fibnminus2=0;
        for(j = 0; j < i; j++){
            fibnminus2 = fibnminus1;
            fibnminus1 = fibn;
            if(j < 2)
                fibn = j;
            else
                fibn = fibnminus1+fibnminus2;                
            printf("%d, ", fibn);
        }
        printf("...\n");
        return 0;
    }else{
        wait();
    }

    return 0;
}