/in/ex4.c: In function 'main':
/in/ex4.c:9:14: warning: format '%lu' expects argument of type 'long unsigned int *', but argument 2 has type 'struct tm *' [-Wformat=]
     scanf("%lu",timeinfo);
              ^
/in/ex4.c:9:5: warning: 'timeinfo' is used uninitialized in this function [-Wuninitialized]
     scanf("%lu",timeinfo);
     ^~~~~~~~~~~~~~~~~~~~~