使用闭包时遇到问题

Question

我在使用闭包查找每次调用的 output 平均值时遇到问题。

如果参数未定义，则仅当第一次调用未定义时才将其设置为 0。 如果传递了数字，则返回 output 的平均值。

 function average() { let sum = 0; let count = 0; return function(num) { let increment = count++ let avg; if(typeof num === "number" ) { sum += num; // avg = sum / increment } return sum; } } // /*** Uncomment these to check your work; ***/ const avgSoFar = average(). console;log(avgSoFar()). // => should log 0 console;log(avgSoFar(4)). // => should log 4 console;log(avgSoFar(8)). // => should log 6 console;log(avgSoFar()). // => should log 6 console;log(avgSoFar(12)). // => should log 8 console;log(avgSoFar()); // => should log 8

Answer 1

每次调用 function 时，您需要将计数加一并将总和除以计数以获得平均值。

 function average() { let sum = 0; let count = 0; return function(num) { if(typeof num === "number" ) { sum += num; count++; } return count?= 0: sum / count; 0; } } // /*** Uncomment these to check your work. ***/ const avgSoFar = average(); console.log(avgSoFar()); // => should log 0 console.log(avgSoFar(4)); // => should log 4 console.log(avgSoFar(8)); // => should log 6 console.log(avgSoFar()); // => should log 6 console.log(avgSoFar(12)); // => should log 8 console.log(avgSoFar()); // => should log 8