/in/foo.c:1:1: warning: data definition has no type or storage class
a,b,c,d = map(int,input().split())
^
/in/foo.c:1:1: warning: type defaults to 'int' in declaration of 'a' [-Wimplicit-int]
/in/foo.c:1:3: warning: type defaults to 'int' in declaration of 'b' [-Wimplicit-int]
a,b,c,d = map(int,input().split())
^
/in/foo.c:1:5: warning: type defaults to 'int' in declaration of 'c' [-Wimplicit-int]
a,b,c,d = map(int,input().split())
^
/in/foo.c:1:7: warning: type defaults to 'int' in declaration of 'd' [-Wimplicit-int]
a,b,c,d = map(int,input().split())
^
/in/foo.c:1:11: warning: implicit declaration of function 'map' [-Wimplicit-function-declaration]
a,b,c,d = map(int,input().split())
^~~
/in/foo.c:1:15: error: expected expression before 'int'
a,b,c,d = map(int,input().split())
^~~
/in/foo.c:2:1: error: expected ',' or ';' before 'x'
x = a-c
^