仓颉 Hello

Hello

// Hello, World!
func fun1(str1:String) {
   println("Output " + str1 + " from fun1.\n")
}

main() {
   var s1 = "Hello, World!"
   println(s1)
   fun1("test")
}

# compile
cjc hello.cj -o hello
# hello 793664(VSCode: 795384)

# result
Hello, World!
Output test from fun1.

C function

• 将调用的函数在 foreign 中定义，基本变量类型改为仓颉类型，变长用 ... 表达
• 结构体定义 @C
• 使用时，用 unsafe{}

编译时，会使用 C 库，如：gcc lib path: /lib/gcc/x86_64-linux-gnu/9。用 cjc ... -V 查看。

foreign {
    func srand(n: Int32): Unit
    func time(): Int32
    func rand(): Int32
}

main() {
   unsafe {
      var n1:Int32 = time()
      srand(n1)
   }

   let r1 = unsafe {
      rand()
   }
   println(r1)
}

封装 C function

// foreign 中不允许重复引用函数
// 建议每个引用函数单独一行
foreign {func srand(n: Int32): Unit}
foreign {func time(): Int32}
foreign {func rand(): Int32}

public func urand(): UInt32 {
    unsafe {
        var n1:Int32 = time()
        srand(n1)
    }

    let r1 = unsafe {
        rand()
    }
    UInt32(r1)
}

main() {
    var n1 = urand()
    println(n1)
}

封装 C function struct

调用方式类似类方法

foreign {func srand(n: Int32): Unit}
foreign {func time(): Int32}
foreign {func rand(): Int32}
public struct UDEF{
    //-- rand    
    public func urand(): UInt32 {
        unsafe {
            var n1:Int32 = time()
            srand(n1)
        }
    
        let r1 = unsafe {
            rand()
        }
        UInt32(r1)
    }
    //== rand
}

main() {
    var udef1 = UDEF()
    var n1 = udef1.urand()
    println(n1)
}