foo.c: In function 'main':
foo.c:4:7: error: expected identifier or '(' before numeric constant
    4 | { int 1234,4321;
      |       ^~~~
foo.c:5:15: error: lvalue required as unary '&' operand
    5 |   scanf("%4d",&1234);
      |               ^
foo.c:6:3: error: 'y' undeclared (first use in this function)
    6 |   y=1234%10*1000+1234/10%10*100+1234/100%10*10+1234/1000
      |   ^
foo.c:6:3: note: each undeclared identifier is reported only once for each function it appears in
foo.c:6:57: error: expected ';' before 'printf'
    6 |   y=1234%10*1000+1234/10%10*100+1234/100%10*10+1234/1000
      |                                                         ^
      |                                                         ;
    7 |     printf("1234=%d,4321=d\n",1234,4321);
      |     ~~~~~~                                               

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