Compilare: user.c: In function ‘main’: user.c:25:9: warning: implicit declaration of function ‘isdigit’ [-Wimplicit-function-declaration] if(!isdigit(ch) && element){ ^ user.c:10:6: warning: unused variable ‘elementP’ [-Wunused-variable] char elementP[10], ch; ^ user.c:15:7: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(file1, "%d", &M); ^ user.c:16:7: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(file1, "%d", &N); ^