Compiler output
prog.c: In function 'keres':
prog.c:22:13: warning: 'return' with a value, in function returning void [enabled by default]
prog.c:41:17: warning: 'return' with a value, in function returning void [enabled by default]
prog.c:49:28: warning: 'return' with a value, in function returning void [enabled by default]
prog.c:74:9: warning: 'return' with a value, in function returning void [enabled by default]
prog.c:78:1: warning: 'return' with a value, in function returning void [enabled by default]
