Question

How to fill a vector with sequence numbers in C++

Answer 1

#include <iostream>
#include <vector>
 
void printVector(std::vector<int> const &v) {
    for (auto const &n: v) {
        std::cout << n << " ";
    }
}
 
int main() {
    std::vector<int> vec(10);
    
    for (unsigned int i = 0; i < vec.size(); i++) {
        vec[i] = i;
    }
      
    printVector(vec);
}

 
 
/*
run:
   
0 1 2 3 4 5 6 7 8 9 
   
*/

 

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Answer 2

#include <iostream>
#include <algorithm>
#include <vector>

struct Number {
   int current;
   Number() { current = 0; }
   int operator()() { return current++; }
} Number;

void printVector(std::vector<int> const &v) {
    for (auto const &n: v) {
        std::cout << n << " ";
    }
}
 
int main() {
    std::vector<int> vec(10);
    
    generate(vec.begin(), vec.end(), Number);
      
    printVector(vec);
}

 
 
/*
run:
   
0 1 2 3 4 5 6 7 8 9 
   
*/

 

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