src.c: In function 'main':
src.c:19:9: error: expected declaration specifiers or '...' before numeric constant
char c(20);
^
src.c:20:9: error: expected declaration specifiers or '...' before numeric constant
char d(20);
^
src.c:22:13: error: 'c' undeclared (first use in this function)
scanf("%s",c);
^
src.c:22:13: note: each undeclared identifier is reported only once for each function it appears in
src.c:24:8: error: 'd' undeclared (first use in this function)
str(c,d);
^