/in/foo.c: In function 'SetInter':
/in/foo.c:39:1: warning: control reaches end of non-void function [-Wreturn-type]
 }  
 ^
/in/foo.c: In function 'main':
/in/foo.c:59:5: warning: 'n12' is used uninitialized in this function [-Wuninitialized]
     SetInter(a1, n1, a2, n2, a12, n12);      
     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/in/foo.c:60:5: warning: 'n13' is used uninitialized in this function [-Wuninitialized]
     SetInter(a1, n1, a3, n3, a13, n13);      
     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~