foo.c: In function 'main':
foo.c:5:5: error: variable-sized object may not be initialized
     int l,m,a,b,aw=0,c[l+1]={0};
     ^~~
foo.c:5:30: warning: excess elements in array initializer
     int l,m,a,b,aw=0,c[l+1]={0};
                              ^
foo.c:5:30: note: (near initialization for 'c')
foo.c:6:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d",&l,&m);
  ^~~~~~~~~~~~~~~~~~~~
foo.c:9:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d",&a,&b);
   ^~~~~~~~~~~~~~~~~~~~

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