2024/10/27

setw()函数

setw在iomanip头文件里面

示例:九九乘法表

#include <iostream>
#include <iomanip>
using namespace std;

int main() {
  for(int i=1; i <= 9; i++){
    for(int j =1; j <= i; j++){
      cout << i << " × " << j << " =" << setw(2) <<i * j << "  ";
      //也可以用 printf("%d × %d = %2d ", i, j, i*j);
    }
  cout << endl;
  }
  return 0;
}

它会输出:

1 × 1 =  1  
2 × 1 =  2  2 × 2 =  4  
3 × 1 =  3  3 × 2 =  6  3 × 3 =  9  
4 × 1 =  4  4 × 2 =  8  4 × 3 = 12  4 × 4 = 16  
5 × 1 =  5  5 × 2 = 10  5 × 3 = 15  5 × 4 = 20  5 × 5 = 25  
6 × 1 =  6  6 × 2 = 12  6 × 3 = 18  6 × 4 = 24  6 × 5 = 30  6 × 6 = 36  
7 × 1 =  7  7 × 2 = 14  7 × 3 = 21  7 × 4 = 28  7 × 5 = 35  7 × 6 = 42  7 × 7 = 49  
8 × 1 =  8  8 × 2 = 16  8 × 3 = 24  8 × 4 = 32  8 × 5 = 40  8 × 6 = 48  8 × 7 = 56  8 × 8 = 64  
9 × 1 =  9  9 × 2 = 18  9 × 3 = 27  9 × 4 = 36  9 × 5 = 45  9 × 6 = 54  9 × 7 = 63  9 × 8 = 72  9 × 9 = 81  

2024/11/10

reverse()函数

/：整除运算，舍去小数部分

%：正数除数余数部分，又称“模运算”

C++默认双精度长度