C到C++ printf

Question

我將如何更改此代碼，使用cout保留格式爲C++？

printf(" %5lu %3d %+1.2f ", nodes, depth, best_score/100.0); 

Answer 1

使用cout.width（n）和cout.precision（N）;

因此，舉例來說：

cout.width(5); 
cout << nodes << " "; 
cout.width(3); 
cout << depth << " "; 
cout.setiosflags(ios::fixed); 
cout.precision(2); 
cout.width(4); 
cout << best_score/100.0 << " " << endl; 

你可以連在一起的事情：

cout << width(5) << nodes << " " << width(3) << depth << " " 
    << setiosflags(ios::fixed) << precision(2) << best_score/100.0 << " " 
    << endl; 

Answer 2

#include <iostream> 
#include <iomanip> 

void func(unsigned long nodes, int depth, float best_score) { 
    //store old format 
    streamsize pre = std::cout.precision(); 
    ios_base::fmtflags flags = std::cout.flags(); 

    std::cout << setw(5) << nodes << setw(3) << depth; 
    std::cout << showpos << setw(4) << setprecision(2) << showpos (best_score/100.); 

    //restore old format 
    std::cout.precision(pre); 
    std::cout.flags(flags); 
} 

Answer 3

說實話，我從來都不喜歡ostream的格式化機制。當我需要做這樣的事情時，我傾向於使用boost::format。

std::cout << boost::format(" %5lu %3d %+1.2f ") % nodes % depth % (best_score/100.0);