Compilare: user.c: In function 'citeste': user.c:19: warning: implicit declaration of function 'exit' user.c:19: warning: incompatible implicit declaration of built-in function 'exit' user.c:22: warning: implicit declaration of function 'atoi' user.c:24: warning: implicit declaration of function 'malloc' user.c:24: warning: incompatible implicit declaration of built-in function 'malloc' user.c: In function 'calculeaza': user.c:75: warning: implicit declaration of function 'abs' user.c: In function 'main': user.c:110: warning: incompatible implicit declaration of built-in function 'exit' user.c:115: warning: control reaches end of non-void function