Compilare: user.c: In function ‘main’: user.c:24:4: warning: implicit declaration of function ‘abs’ [-Wimplicit-function-declaration] if(abs(max2)>max1) ^ user.c:47:2: warning: implicit declaration of function ‘close’ [-Wimplicit-function-declaration] close(f_out); ^ user.c:8:8: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f_in, "%d %d", &N, &M); ^ user.c:14:10: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f_in, "%d", &A[i][j]); ^