Compilare: main.cpp: In function 'void matrix_exp(int)': main.cpp:28:7: warning: variable 'A' set but not used [-Wunused-but-set-variable] int A[3][3]; ^ main.cpp: In function 'int main()': main.cpp:63:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("fibsum.in", "r", stdin); ^ main.cpp:64:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("fibsum.out", "w", stdout); ^ main.cpp:80:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ main.cpp:84:31: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &lft, &rght); ^