Print an Integer by using only putchar

#include<stdio.h>
main(int argc, char **argv)
{
    int i, n, rev, lz = 0;
    if(argc > 1) {
        n = atoi(argv[1]);
    } else {
        printf("Enter the number : ");
        scanf("%d", &n);
    }
    rev = 0;
    lz = 0;
    while(n != 0) {
        if(rev == 0 && n%10 == 0) {
            lz++;
        }
        rev = rev*10 + n%10;
        n = n/10;
    }
    while(rev != 0) {
        putchar(rev%10 + '0');
        rev = rev/10;
    }
    while(lz--) {
        printf("0");
    }
    printf("\n");
}