go version :1.12 第三题 错误: src/demo1/main.go:4:7: invalid character literal (more than one character) src/demo1/main.go:4:12: cannot convert "123" (type untyped string) to type rune src/demo1/main.go:4:12: invalid operation: '\u0000' + "123" (mismatched types rune and string)