Compilare: user.c: In function ‘main’: user.c:13:1: warning: implicit declaration of function ‘sqrt’ [-Wimplicit-function-declaration] fprintf(file2, "%d", sqrt(N)); ^ user.c:13:22: warning: incompatible implicit declaration of built-in function ‘sqrt’ [enabled by default] fprintf(file2, "%d", sqrt(N)); ^ user.c:13:1: warning: format ‘%d’ expects argument of type ‘int’, but argument 3 has type ‘double’ [-Wformat=] fprintf(file2, "%d", sqrt(N)); ^ user.c:12:7: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(file1, "%d", &N); ^