foo.c: In function 'main':
foo.c:7:14: error: redeclaration of 'c' with no linkage
    7 |          int c=a+b;
      |              ^
foo.c:5:13: note: previous declaration of 'c' with type 'int'
    5 |     int a,b,c,d,e;
      |             ^
foo.c:8:14: error: redeclaration of 'd' with no linkage
    8 |          int d=a*b;
      |              ^
foo.c:5:15: note: previous declaration of 'd' with type 'int'
    5 |     int a,b,c,d,e;
      |               ^
foo.c:9:14: error: redeclaration of 'e' with no linkage
    9 |          int e=a%b;
      |              ^
foo.c:5:17: note: previous declaration of 'e' with type 'int'
    5 |     int a,b,c,d,e;
      |                 ^

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