Compilare: main.cpp: In function 'void test_functions()': main.cpp:14:9: warning: variable 'n' set but not used [-Wunused-but-set-variable] int n; ^ main.cpp:15:10: warning: unused variable 'x' [-Wunused-variable] long x; ^ main.cpp:16:12: warning: unused variable 'y' [-Wunused-variable] double y; ^ main.cpp:17:10: warning: unused variable 's1' [-Wunused-variable] char s1[100],s2[100]; ^~ main.cpp:17:18: warning: unused variable 's2' [-Wunused-variable] char s1[100],s2[100]; ^~ main.cpp:18:13: warning: unused variable 'p' [-Wunused-variable] char c,*p; ^ main.cpp:19:14: warning: 'c' is used uninitialized in this function [-Wuninitialized] n=isalpha(c); ~~~~~~~^~~