Question

如何使用cout获得“绝对定位”列，左对齐文本并右对齐数字？

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

struct Human {
    char name[20];
    char name2[20];
    char name3[20];
    double pts;
};

int main() {
    int i;
    Human myHumen[3] = {
        {"Mr", "Alan", "Turing", 12.25},
        {"Ms", "Ada", "Lovelace", 15.25},
        {"Sir",  "Edgar Allan", "Poe", 45.25}
    };
    cout << "Name1" << setw(22) << "Name2" << setw(22) << "Name3" << setw(22) << "Rating" <<endl;
    cout << "-----------------------------------------------------------------------\n";
    for(i = 0; i < 3; i++) {
        cout << myHumen[i].name << setw(22) << myHumen[i].name2 << setw(22) << myHumen[i].name3 << setw(20) << myHumen[i].pts << endl;
    }//this didn't do nice printouts, with leftalign for text and rightalign with numbers
}

Answer 1

您使用“左”和“右”操纵器：

cout << std::left  << std::setw(30) << "This is left aligned"
     << std::right << std::setw(30) << "This is right aligned";

包含文字+数字的示例：

typedef std::vector<std::pair<std::string, int> > Vec;
std::vector<std::pair<std::string, int> > data;
data.push_back(std::make_pair("Alan Turing", 125));
data.push_back(std::make_pair("Ada Lovelace", 2115));

for(Vec::iterator it = data.begin(), e = data.end(); it != e; ++it)
{
    cout << std::left << std::setw(20) << it->first
         << std::right << std::setw(20) << it->second << "\n";
}

打印哪些：

Alan Turing                          125
Ada Lovelace                        2115

Answer 2

这稍微不受欢迎，但你可以使用printf来实现这种快速程序。格式化字符串更容易理解和使用（给某人同时浏览iostream和printf）。

#include <cstdio>
#include <iostream>
#include <iomanip>
#include <string>

struct Human {
  char name[20];   // consider using std::string
  char name2[20];
  char name3[20];
  double pts;
};

int main() {
  using namespace std;
  Human people[3] = {
    {"Mr", "Alan", "Turing", 12.25},
    {"Ms", "Ada", "Lovelace", 15.25},
    {"Sir",  "Edgar Allan", "Poe", 45.25}
  };
  printf("%-22s%-22s%-22s%20s\n", "Name1", "Name2", "Name3", "Rating");
  cout << string(22 * 3 + 20, '-') << '\n';
  for (int i = 0; i < 3; i++) {
    Human const& h = people[i];
    printf("%-22s%-22s%-22s%20f\n", h.name, h.name2, h.name3, h.pts);
  }
  return 0;
}

安全（默认情况下，请参阅std :: sync_with_stdio）来混合使用cout和printf，一个好的编译器也可以为你检查格式字符串的类型（-Wall in gcc）。

使用C ++中的cout在打印输出中进行绝对定位？

2 个答案: