Command Line Progress Bar

I frequently need a progress bar for applications, in order to visualize what is going on in the application. Following is a simple progress bar implemented in three different languages, C++, Clojure and Java. 

[================>                                 ]   33%

They all look the same, just call the appropriate function with the percentage to show.

C++, 

void printProgBar( int percent ){
  std::string bar;

  for(int i = 0; i < 50; i++){
    if( i < (percent/2)){
      bar.replace(i,1,"=");
    }else if( i == (percent/2)){
      bar.replace(i,1,">");
    }else{
      bar.replace(i,1," ");
    }
  }

  std::cout<< "\r" "[" << bar << "] ";
  std::cout.width( 3 );
  std::cout<< percent << "%     " << std::flush;
}

Clojure,

Tom Hicks in the comments provided a more elegant version than mine, by computing the sequences of characters that we need directly. 

(defn print-progress-bar [percent]
  (let [bar (StringBuilder. "[")] 
    (doseq [i (range 50)]
      (cond (< i (int (/ percent 2))) (.append bar "=")
            (= i (int (/ percent 2))) (.append bar ">")
            :else (.append bar " ")))
    (.append bar (str "] " percent "%     "))
    (print "\r" (.toString bar))
    (flush)))

Java, 

public static void printProgBar(int percent){
    StringBuilder bar = new StringBuilder("[");

    for(int i = 0; i < 50; i++){
        if( i < (percent/2)){
            bar.append("=");
        }else if( i == (percent/2)){
            bar.append(">");
        }else{
            bar.append(" ");
        }
    }

    bar.append("]   " + percent + "%     ");
    System.out.print("\r" + bar.toString());
}
Tags: clojure c++ java