Eroare de compilare: user.cpp:4: error: ‘fopen’ was not declared in this scope user.cpp:5: error: ‘fopen’ was not declared in this scope user.cpp: In function ‘int main()’: user.cpp:12: error: ‘fscanf’ was not declared in this scope user.cpp:25: error: ‘fprintf’ was not declared in this scope user.cpp:26: warning: ignoring return value of ‘int system(const char*)’, declared with attribute warn_unused_result