Compilare: user.cpp: In function ‘int main()’: user.cpp:126:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(unsigned int i = 2;i <= N;i++) ^ user.cpp:127:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(unsigned int j = i + 1;j <= N;j++) ^ user.cpp:128:45: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(unsigned int k = j + 1;k <= N;k++) { ^ user.cpp:129:37: warning: narrowing conversion of ‘i’ from ‘unsigned int’ to ‘int’ inside { } [-Wnarrowing] int nr1[] = {i, j, k}; ^ user.cpp:129:37: warning: narrowing conversion of ‘j’ from ‘unsigned int’ to ‘int’ inside { } [-Wnarrowing] user.cpp:129:37: warning: narrowing conversion of ‘k’ from ‘unsigned int’ to ‘int’ inside { } [-Wnarrowing] user.cpp: In function ‘char next()’: user.cpp:18:41: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buf, 1, BUF, fin), pos = 0; ^