我是 C 新手。我正在使用 STL Containers。我將 AnimalWeightCAT 映射到以公里為單位的距離旅行的唯一值。使用此代碼
#include <iostream>
#include <map>
#include <sstream>
int main() {
std::istringstream file(
"3 138 3 239 3 440 3 241 3 462 3 432 3 404 2 435 2 514 2 565 3 328 3 "
"138 5 401 5 142 5 404 5 460 5 472 2 418 5 510 2");
// some typedefs to make it simpler:
typedef int AnimalWeightCAT_t;
typedef int distance_t;
typedef int count_t;
typedef std::map<distance_t, count_t> distcount_t;
typedef std::map<AnimalWeightCAT_t, distcount_t> AWeightDistance;
AWeightDistance AWeightDistanceCount; // map AnimalWeightCAT -> distances with counts
AnimalWeightCAT_t AnimalWeightCAT; // temporary variable to read a AnimalWeightCAT
distance_t dist; // temporary variable to read a distance
// read AnimalWeightCAT and distance until the file is depleated and use AnimalWeightCAT and dist as
// keys in the outer and inner map and increase the count:
while (file >> AnimalWeightCAT >> dist) AWeightDistanceCount[AnimalWeightCAT][dist];
for(AWeightDistance::iterator adit= AWeightDistanceCount.begin(); adit!= AWeightDistanceCount.end(); adit) {
std::cout << "AnimalWeightCAT: " << adit->first << '\n';
for(distcount_t::iterator dcit = adit->second.begin();dcit != adit->second.end(); dcit){
std::cout << '\t' << dcit->first << ' ' << dcit->second << '\n';
}
}
}
我如何通過在 C 中使用 map找到AnimalWeightCAT索引中的distict數？iterator adit上面的代碼顯示以下輸出
Output:
AnimalWeightCAT: 2
418 1
435 1
514 1
565 1
AnimalWeightCAT: 3
138 2
239 1
241 1
328 1
404 1
432 1
440 1
462 1
AnimalWeightCAT: 5
142 1
401 1
404 1
460 1
472 1
510 1
我想要這種輸出。如何？
AnimalWeightCAT: 2 count = 4
AnimalWeightCAT: 3 count = 8
AnimalWeightCAT: 5 count = 6
uj5u.com熱心網友回復：
因為第二張地圖的數量adit->second.size()就足夠了，所以你的最后一個回圈，為了看起來像你想要的，必須是：
for(AWeightDistance::iterator adit = AWeightDistanceCount.begin();
adit != AWeightDistanceCount.end(); adit)
{
std::cout << "AnimalWeightCAT: " << adit->first
<< " count: " << adit->second.size() << '\n';
}
或更簡單，使用基于范圍的 for 回圈：
for(auto&&[awc, dist_count] : AWeightDistanceCount) {
std::cout << "AnimalWeightCAT: " << awc
<< " count: "<< dist_count.size() << '\n';
}
轉載請註明出處，本文鏈接：https://www.uj5u.com/net/490206.html