Compilare: user.c: In function ‘main’: user.c:16:1: warning: implicit declaration of function ‘sqrt’ [-Wimplicit-function-declaration] sqrtN = sqrt(copyOfN); ^ user.c:16:9: warning: incompatible implicit declaration of built-in function ‘sqrt’ [enabled by default] sqrtN = sqrt(copyOfN); ^ user.c:32:9: warning: format ‘%lld’ expects argument of type ‘long long int’, but argument 4 has type ‘int’ [-Wformat=] fprintf(file2, "%lld %lld\n", (2*N/divisorsOf2N[k - i] - divisorsOf2N[k - i] + 1) / 2, divisorsOf2N[k - i]); ^ user.c:35:5: warning: format ‘%lld’ expects argument of type ‘long long int’, but argument 4 has type ‘int’ [-Wformat=] fprintf(file2, "%lld %lld\n", (2*N/divisorsOf2N[i] - divisorsOf2N[i] + 1) / 2, divisorsOf2N[i]); ^ user.c:43:8: warning: format ‘%lld’ expects argument of type ‘long long int’, but argument 4 has type ‘int’ [-Wformat=] fprintf(file2, "%lld %lld\n", (2*N/divisorsOf2N[k] - divisorsOf2N[k] + 1) / 2, divisorsOf2N[k]); ^ user.c:14:7: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(file1, "%lld", &N); ^