标签：测试 cte capacity span ret iostream 尽心 const bsp
1.assign 用于初始化
2.resize 改变capacity,与size
3.reserve 改变capacity，不改变size
超过size的capacity不可直接访问，可通过push_back追加，若size < capacity, push_back操作不尽心内存分配。
测试代码：
#include <stdio.h> #include <iostream> #include <vector> #include <string> void ShowInfo(const std::string& info, const std::vector<char>& vec) { std::cout << info << ":" << "capacity=" << vec.capacity() << ", " << "size=" << vec.size() << std::endl; } int main() { std::vector<char> vecTest; vecTest.assign(5, 0); ShowInfo("assign", vecTest); vecTest.resize(10); ShowInfo("resize", vecTest); vecTest.reserve(15); ShowInfo("reserve", vecTest); vecTest.resize(10); ShowInfo("resize to 10", vecTest); system("pause"); return 0; }
结果：
assign:capacity=5, size=5 resize:capacity=10, size=10 reserve:capacity=15, size=10 resize to 10:capacity=15, size=10
std::vector中assign resize reserve的区别
标签：测试 cte capacity span ret iostream 尽心 const bsp
原文地址：http://www.cnblogs.com/ziyu-trip/p/7064041.html
