[英]Why my program alerting undefined value
var cars = ["nano", "bmw"];
var bikes = ["pulsar", "splander"];
var con = [];
var foundCars = [];
var foundBikes = [];
var notFoundTransport =[];
for(var i = 0; i<cars.length; i++){
con = prompt("enter your tranport name");
if(con[i] == cars[i]){
foundCars.push(con[i]);
}
}
for(var i = 0; i<2; i++){
alert(foundCars[i]);
}
为什么在警告foundcars数组后显示未定义的值,例如nano bmw,它是警报,未定义,未定义的请让我知道我错了。
首先,您需要将提示结果添加到con数组中的适当位置。
然后,您应该考虑到foundCars的长度(而不是硬编码的2)来遍历数组。
var cars = ["nano", "bmw"];
var bikes = ["pulsar", "splander"];
var con = [];
var foundCars = [];
var foundBikes = [];
var notFoundTransport =[];
for(var i = 0; i<cars.length; i++){
con[i] = prompt("enter your tranport name");
if(con[i] == cars[i]){
foundCars.push(con[i]);
}
}
for(var i = 0; i<foundCars.length; i++){
alert(foundCars[i]);
}
因为foundCars
为空
您应该将这样的车用于发现的汽车。
for(var i = 0; i<cars.length; i++){
con = prompt("enter your tranport name");
for(var p = 0; p<cars.length; p++){
if(con == cars[p]){
foundCars.push(con);
}
}
}
并使用for(var i = 0; i<foundCars.length; i++)
for(var i = 0; i<2; i++)
请检查:
var cars = ["nano", "bmw"];
var bikes = ["pulsar","splander"];
var con = [];
var foundCars = [];
var foundBikes = [];
var notFoundTransport =[];
var found = false;
var checkExist = false;
for(var i = 0; i<2; i++){
con[i] = prompt("enter your tranport name");
}
for(var i = 0; i<con.length; i++){
for(var j = 0; j<con.length; j++){
if(con[i] == cars[j]){
foundCars.push(con[i]);
found = true;
checkExist = true;
}else if(con[i] == bikes[j]){
foundBikes.push(con[i]);
found = true;
checkExist = true;
}else if(con[i]!=cars[j]&&con[i]!=bikes[j]&&found==false&&j!=0){
notFoundTransport.push(con[i]);
found = true;
}
}
found = false;
}
console.log(foundCars);
console.log(foundBikes);
console.log(notFoundTransport);
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