/in/foo.c: In function 'dfs':
/in/foo.c:3:15: error: 'true' undeclared (first use in this function)
     used[u] = true;
               ^~~~
/in/foo.c:3:15: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c: In function 'makeConnected':
/in/foo.c:19:5: warning: implicit declaration of function 'memset' [-Wimplicit-function-declaration]
     memset(edgesColSize, 0, sizeof(edgesColSize));
     ^~~~~~
/in/foo.c:19:5: warning: incompatible implicit declaration of built-in function 'memset'
/in/foo.c:19:5: note: include '<string.h>' or provide a declaration of 'memset'
/in/foo.c:25:20: warning: implicit declaration of function 'malloc' [-Wimplicit-function-declaration]
         edges[i] = malloc(sizeof(int) * edgesColSize[i]);
                    ^~~~~~
/in/foo.c:25:20: warning: incompatible implicit declaration of built-in function 'malloc'
/in/foo.c:25:20: note: include '<stdlib.h>' or provide a declaration of 'malloc'