c++入门
endl用于向流的末尾部位加入换行符cout代表显示器cout << x操作就相当于把x的值输出到显示器
输入 Hello World
# include<iostream> using namespace std; int main() { cout <<"Hello World!\n"; }
输入输出
#include <iostream> using namespace std; int main() { int a, b, result; cout << "please input two number:\n"; cin >> a >> b; result = 3 * a - 2 * b + 1; cout << "result is " << result << endl; }
使用函数
#include<iostream> #include<cmath> using namespace std; double max(double x, double y); int main() { double a, b, c; cout << "input two number:\n"; cin >> a >> b; c = max(a, b); cout << "maximum=" << c << "\n"; cout << "the squart of maximum=" << sqrt(c); } double max(double x, double y) { if (x > y) return x; else return y; }
函数定义包含函数声明
#include<iostream> #include<cmath> using namespace std; double max(double x, double y) { // 既是函数定义又是函数声明 if (x > y) return x; else return y; } int main() { double a, b, c; cout << "input two numbers:\n"; cin >> a >> b; c = max(a, b); cout << "the squart of maximum=" << sqrt(c); }