[英]How to print all the nodes number of a tree
我想打印這棵樹內的所有“數量”元素,但據我測試,如果節點有 2 個以上的孩子,它不會打印其他的,就像下面的輸出一樣,我我的想法不多了。 這是我的實際代碼:
function preOrder(tree) {
var qntChildren = 0
try{
console.log(tree.quantity)
if (tree.childrens || tree.quantity) {
preOrder(tree.childrens[0])
}
}catch(e) {
preOrder(tree.childrens[qntChildren + 1])
}
}
preOrder(treeModel)
這是樹:
var treeModel = {
"quantity": 5,
"childrens": [
{
"quantity": 3,
"childrens": [
{
"tech": "B",
"quantity": 1,
"childrens": []
},
{
"tech": "C",
"quantity": 4,
"childrens": []
},
{
"tech": "C",
"quantity": 6,
"childrens": []
}
]
}
]
}
輸出是:
5
3
1
4
c:\Users\gabri\Área de Trabalho\Estágio\Arvore.js:41
preOrder(tree.childrens[qntChildren + 1])
^
TypeError: Cannot read property 'childrens' of undefined
at preOrder (c:\Users\gabri\Área de Trabalho\Estágio\Arvore.js:41:23)
at preOrder (c:\Users\gabri\Área de Trabalho\Estágio\Arvore.js:41:9)
at Object.<anonymous> (c:\Users\gabri\Área de Trabalho\Estágio\Arvore.js:46:1)
at Module._compile (internal/modules/cjs/loader.js:1063:30)
at Object.Module._extensions..js (internal/modules/cjs/loader.js:1092:10)
at Module.load (internal/modules/cjs/loader.js:928:32)
at Function.Module._load (internal/modules/cjs/loader.js:769:14)
at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:72:12)
at internal/main/run_main_module.js:17:47
您可以使用 for 循環和遞歸來做到這一點。
var treeModel = { quantity: 5, childrens: [ { quantity: 3, childrens: [ { tech: 'B', quantity: 1, childrens: [] }, { tech: 'C', quantity: 4, childrens: [] }, { tech: 'C', quantity: 6, childrens: [] }, ], }, ], }; function getQuantity(tree) { console.log(tree.quantity); for (const child of tree.childrens) getQuantity(child); } getQuantity(treeModel)
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