lcm_gcd.c

#include<stdlib.h>
#include<stdio.h>

long int gcd(long int a, long int b){
	if(b==0) return a;
	else return gcd(b,a%b);
}
long int lcm(long int a, long int b){
	return a*b/gcd(a,b);
}
long int lcm_arr(long int *arr, int n){
        if(n==1) return arr[0];
        else{
                arr[n-2]=lcm(arr[n-1],arr[n-2]);
                return lcm_arr(arr,n-1);
        }
}
/**
* USAGE: ./a.out 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 
**/
int main(int argc, char *argv[]){
	if(argc<2) return 1;
	long int *arr=malloc((argc-2)*sizeof(long int));
	for(int i=1;i<argc;i++){
		*(arr+i-1) = atoi(argv[i]);
	}
	printf("lcm=%ld",lcm_arr(arr,argc-1));
	free(arr);
	return 0;
}