c++ STL accmulate

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sum (1)

template <class InputIterator, class T>   T accumulate (InputIterator first, InputIterator last, T init);

custom (2)

template <class InputIterator, class T, class BinaryOperation>   T accumulate (InputIterator first, InputIterator last, T init,                 BinaryOperation binary_op);

第一种形式：对于数列 a1,a2,a3,a4---------运用上述算法的效果为：init +a1+a2+a3+a4

第二种形式：对于数列 a1,a2,a3,a4---------运用上述算法的效果为：init binary_op a1 binary_op a2 binary_op a3 binary_op
a4

#include "algostuff.hpp"

#include <iterator>
#include <ostream>
#include <numeric>
using namespace std;

int main(){
vector<int> coll;
INSERT_ELEMENTS(coll,1,9);
PRINT_ELEMENTS(coll);
cout<<endl;

cout<<"sum:"<<accumulate(coll.begin(),coll.end(),0)<<endl;

cout<<"sum:"<<accumulate(coll.begin(),coll.end(),-100)<<endl;

cout<<"product:"<<accumulate(coll.begin(),coll.end(),1,multiplies<int>())<<endl;

cout<<"product:"<<accumulate(coll.begin(),coll.end(),0,multiplies<int>())<<endl;

return 0;

}

编译输出：

1 2 3 4 5 6 7 8 9
sum:45
sum:-55
product:362880
product:0

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