foo.c: In function 'main':
foo.c:8:2: error: 'for' loop initial declarations are only allowed in C99 mode
  for(int i=1;i<=m;i++)
  ^
foo.c:8:2: note: use option -std=c99 or -std=gnu99 to compile your code
foo.c:9:3: warning: too many arguments for format [-Wformat-extra-args]
   scanf("&d",&a[i]);
   ^
foo.c:10:10: error: redefinition of 'i'
  for(int i=1;i<=m;i++)
          ^
foo.c:8:10: note: previous definition of 'i' was here
  for(int i=1;i<=m;i++)
          ^
foo.c:10:2: error: 'for' loop initial declarations are only allowed in C99 mode
  for(int i=1;i<=m;i++)
  ^
foo.c:11:3: error: 'for' loop initial declarations are only allowed in C99 mode
   for(int j=1;j<=m;j++)
   ^
foo.c:12:4: error: 'for' loop initial declarations are only allowed in C99 mode
    for(int k=1;k<=m;k++)
    ^