src.c:21:8: error: initializer element is not constant
PI=4*PI;
^
src.c:22:12: error: expected declaration specifiers or '...' before string constant
printf("%f\n",PI);
^
src.c:22:19: error: expected declaration specifiers or '...' before 'PI'
printf("%f\n",PI);
^
src.c:23:5: error: expected identifier or '(' before 'return'
return 0;
^
src.c:24:1: error: expected identifier or '(' before '}' token
}
^