Compilare: main.c: In function 'main': main.c:42:17: warning: format '%d' expects argument of type 'int *', but argument 3 has type 'uint64_t * {aka long unsigned int *}' [-Wformat=] fscanf(inptr,"%d %d", &n, &a); ^ main.c:45:21: warning: format '%lld' expects argument of type 'long long int', but argument 3 has type 'int' [-Wformat=] fprintf(outptr,"%lld", fast_exp(n,p)); ^ main.c:42:2: warning: ignoring return value of 'fscanf', declared with attribute warn_unused_result [-Wunused-result] fscanf(inptr,"%d %d", &n, &a); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~