Compilare: user.c: In function ‘main’: user.c:14:9: warning: implicit declaration of function ‘sqrt’ [-Wimplicit-function-declaration] int j,var=sqrt(b)+1,div=0; ^ user.c:14:19: warning: incompatible implicit declaration of built-in function ‘sqrt’ [enabled by default] int j,var=sqrt(b)+1,div=0; ^