let a=7 let b=8 let a=a-1 let b=a print a+b end

let a=7 let b=8 let a=a-1 let b=a print a+b end
let a=7 let b=8 let a=a-1 let b=a print a+b end

let a=7 let b=8 let a=a-1 let b=a print a+b end
12.a=a-1的意思是把a-1的值赋给a,则现在,a=6,再b=a,把现在的a赋给b,b=6.printa+b,的值为6+6,即12