Comparison between C/C++ and Java

Labor für Technische Informatik
Praktikum VSP
KLC/SLZ
Comparison between C/C++ and Java
C/C++
Java
#include <iostream>
#include <stdlib.h>
#include <time.h>
import java.util.Date;
using namespace std;
// for cout,endl etc.
public class LapTimer {
private int clickCount;
class LapTimer {
private:
int clickCount;
public:
LapTimer() {
clickCount = 0;
}
public LapTimer() {
clickCount = 0;
}
public String click() {
Date tm = new Date();
void click(char* cbuffer) {
time_t t_now;
// Formatting numbers and
// chars into a string
return String.format(
"Time: %02d:%02d:%02d",
tm.getHours(),
tm.getMinutes (),
tm.getSeconds());
time(&t_now);
struct tm* lt_now = localtime(&t_now);
// Formatting numbers and
// chars into a (C-) string
sprintf(cbuffer, \
"Time: %02d:%02d:%02d", \
lt_now->tm_hour,
lt_now->tm_min, lt_now->tm_sec);
}
public static void main(String[] args) {
int iMax = 5;
String cbuffer1 = null;
}
};
int main(int argc, char *argv[]) {
//
^-length
^-argument array
int iMax = 5;
char cbuffer1[255];
if (args.length > 1)
iMax = Integer.parseInt(args[0]);
// args[0] is first parameter
LapTimer myLapTimer = new LapTimer();
if (argc > 1) iMax = atoi(argv[1]);
// argv[1] is first parameter
for (int i=0; i<iMax; i++) {
try {
// milliseconds (!)
Thread.sleep(1000);}
catch (InterruptedException e){}
LapTimer* myLapTimer = new LapTimer();
for (int i=0; i<iMax; i++) {
sleep(1); // seconds (!)
myLapTimer->click(cbuffer1);
cout << cbuffer1 << endl;
}
}
return 0;
}
}
cbuffer1 = myLapTimer.click();
System.out.println(cbuffer1);
System.exit(0);
}
Remarks:
• getHours(), getMinutes() and getSeconds() from the Java class Date are deprecated. They are merely used
here for better comparison to C.
• Declarations and Definitions are normally written to individual files, i.e. header files (*.h ) and source files
*.cpp) in C++. See example overpages.
• Documentation on C und C++ library functions (time(), sprintf() etc.) can be found in the man-pages.
Some of the functions used here are originally C functions. They are also available in C++.
A more detailed introduction to C++ can be obtained here.
Labor für Technische Informatik
Praktikum VSP
Breaking down the sample into header and source files
Header file (LapTimer.h):
#ifndef LAPTIMER_H_
#define LAPTIMER_H_
class LapTimer {
public:
LapTimer();
virtual ~LapTimer();
void click(char* cbuffer);
};
#endif /* LAPTIMER_H_ */
Source file (LapTimer.cpp):
#include <iostream>
#include <stdlib.h>
#include <time.h>
using namespace std;
//
for cout,endl etc
class LapTimer {
private:
int clickCount;
public:
LapTimer() {
clickCount = 0;
}
void click(char* cbuffer) {
time_t t_now;
time(&t_now);
struct tm* lt_now = localtime(&t_now);
// Formatting numbers and chars into a (C-) string
sprintf(cbuffer, "Time: %02d:%02d:%02d", \
lt_now->tm_hour, lt_now->tm_min, lt_now->tm_sec);
}
};
int main(int argc, char *argv[]) {
int iMax = 5;
char cbuffer1[255];
//
length and argument array
if (argc > 1) iMax = atoi(argv[1]);
// argv[1] is first parameter
LapTimer* myLapTimer = new LapTimer();
for (int i=0; i<iMax; i++) {
sleep(1); // seconds (!)
myLapTimer->click(cbuffer1);
cout << cbuffer1 << endl;
}
return 0;
}
KLC/SLZ