src.c:1:10: error: empty character constant
n1=input('')
^
src.c:1:4: error: initializer element is not constant
n1=input('')
^
src.c:2:1: error: expected ',' or ';' before 'n2'
n2=input('')
^
src.c:2:10: error: empty character constant
n2=input('')
^
src.c:3:10: error: empty character constant
n3=input('')
^