Commit d84748
2024-11-17 13:36:49 Qwas: Save c++入门| /dev/null .. "b/cpp/c++\345\205\245\351\227\250.md" | |
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| + | # 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 |
| + | |
| + | ```cpp |
| + | # include<iostream> |
| + | using namespace std; |
| + | int main() { |
| + | cout <<"Hello World!\n"; |
| + | } |
| + | ``` |
| + | |
| + | ## 输入输出 |
| + | |
| + | ```cpp |
| + | #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 |
| + | |
| + | ```cpp |
| + | #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 |
| + | |
| + | ```cpp |
| + | #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); |
| + | } |
| + | ``` |