Compilare: user.c: In function ‘main’: user.c:12:5: warning: implicit declaration of function ‘malloc’ [-Wimplicit-function-declaration] b=(char**)malloc(sizeof(char*)*y); ^ user.c:12:15: warning: incompatible implicit declaration of built-in function ‘malloc’ [enabled by default] b=(char**)malloc(sizeof(char*)*y); ^ user.c:41:25: warning: implicit declaration of function ‘realloc’ [-Wimplicit-function-declaration] realloc(b[i],sizeof(char)*z); ^ user.c:41:25: warning: incompatible implicit declaration of built-in function ‘realloc’ [enabled by default] user.c:67:17: warning: incompatible implicit declaration of built-in function ‘realloc’ [enabled by default] realloc(b,sizeof(char*)*y); ^ user.c:7:31: warning: unused variable ‘m’ [-Wunused-variable] int i=0,j=0,x,y=100,z=100,m=0;; ^ user.c:7:17: warning: variable ‘x’ set but not used [-Wunused-but-set-variable] int i=0,j=0,x,y=100,z=100,m=0;; ^