/in/foo.c: In function 'main':
/in/foo.c:5:10: warning: format '%d' expects argument of type 'int *', but argument 2 has type 'float *' [-Wformat=]
  scanf("%d%d%d",&a,&m,&k);
          ^
/in/foo.c:5:12: warning: format '%d' expects argument of type 'int *', but argument 3 has type 'float *' [-Wformat=]
  scanf("%d%d%d",&a,&m,&k);
            ^
/in/foo.c:5:14: warning: format '%d' expects argument of type 'int *', but argument 4 has type 'float *' [-Wformat=]
  scanf("%d%d%d",&a,&m,&k);
              ^
/in/foo.c:14:2: warning: 'sum' may be used uninitialized in this function [-Wmaybe-uninitialized]
  printf("%f ",sum);
  ^~~~~~~~~~~~~~~~~