Compiler output
prog.c: In function 'keres':
prog.c:31:13: warning: 'return' with a value, in function returning void [enabled by default]
prog.c:50:17: warning: 'return' with a value, in function returning void [enabled by default]
prog.c:58:28: warning: 'return' with a value, in function returning void [enabled by default]
prog.c:87:9: warning: 'return' with a value, in function returning void [enabled by default]
prog.c:112:9: warning: 'return' with a value, in function returning void [enabled by default]
prog.c:115:1: warning: 'return' with a value, in function returning void [enabled by default]
