input/code.cpp: In function 'int main(int, char**)':
input/code.cpp:10:21: warning: format '%i' expects argument of type 'int*', but argument 2 has type 'int_fast64_t* {aka long int*}' [-Wformat=]
std::scanf("%i", &n);
~~^
input/code.cpp:11:47: error: 'sqrtf' is not a member of 'std'
int_fast64_t viimeinen = (int_fast64_t)(std::sqrtf((8*n+1)/4)-0.5);
^~~~~
input/code.cpp:11:47: note: suggested alternative: 'sqrt'
int_fast64_t viimeinen = (int_fast64_t)(std::sqrtf((8*n+1)/4)-0.5);
^~~~~
sqrt
input/code.cpp:12:32: warning: format '%i' expects argument of type 'int', but argument 2 has type 'int_fast64_t {aka long int}' [-Wformat=]
std::printf("%i \n", viimeinen);
^
input/code.cpp:16:23: warning: format '%i' expects argument of type 'int', but argument 2 has type 'int_fast64_t {aka long i...