Compilare: user.c: In function ‘main’: user.c:49:14: warning: unused variable ‘j’ [-Wunused-variable] long long i, j, t, Xn, sigma = 0, k = 3; ^ user.c:49:11: warning: unused variable ‘i’ [-Wunused-variable] long long i, j, t, Xn, sigma = 0, k = 3; ^ user.c: In function ‘Expo’: user.c:43:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.c: In function ‘main’: user.c:54:7: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(file1, "%lld", &A); ^ user.c:55:7: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(file1, "%lld", &B); ^ user.c:56:7: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(file1, "%lld", &C); ^ user.c:57:7: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(file1, "%lld", &X1); ^ user.c:58:7: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(file1, "%lld", &X2); ^ user.c:59:7: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(file1, "%lld", &N); ^