Compilare: user.c: In function ‘Date’: user.c:13:17: warning: implicit declaration of function ‘malloc’ [-Wimplicit-function-declaration] v = (struct gutui*)malloc(N*sizeof(struct gutui)); ^ user.c:13:24: warning: incompatible implicit declaration of built-in function ‘malloc’ [enabled by default] v = (struct gutui*)malloc(N*sizeof(struct gutui)); ^ user.c: In function ‘main’: user.c:59:9: warning: unused variable ‘i’ [-Wunused-variable] int i,k=0; ^