c - C - 格式化字符数组，如 printf

Question

我想像这样格式化交流字符串printf。例如：

char string[] = "Your Number:%i";
int number = 33;
// String should now be "Your Number:33"

有什么图书馆或我可以做到这一点的好方法吗？

Answer 1

sprintf(char* out, const char* format, ... );像这样使用：

int main() {
  char str[] = "Your Number:%d";
  char str2[1000];
  int number = 33;
  sprintf(str2,str,number);
  printf("%s\n",str2);
  return 0;
}

输出：

---------- Capture Output ----------
> "c:\windows\system32\cmd.exe" /c c:\temp\temp.exe
Your Number:33

> Terminated with exit code 0.

Answer 2

sprintf - http://linux.die.net/man/3/sprintf

Answer 3

为了调试我的 Arduino 草图，我习惯性地使用这个解决方案，取自Madivad对如何在字符串中打印多个变量的回答？.

您将此功能添加到您的草图中，这将允许您使用printf()，尽管它会因float,而失败%f。

// Function that printf and related will use to print
int serial_putchar(char c, FILE* f) {
    if (c == '\n') serial_putchar('\r', f);
    return Serial.write(c) == 1? 0 : 1;
}

添加全局

FILE serial_stdout;

并把这是setup()

fdev_setup_stream(&serial_stdout, serial_putchar, NULL, _FDEV_SETUP_WRITE);
stdout = &serial_stdout;

一个示例草图是：

// Function that printf and related will use to print
int serial_putchar(char c, FILE* f) {
    if (c == '\n') serial_putchar('\r', f);
    return Serial.write(c) == 1? 0 : 1;
}

FILE serial_stdout;


void setup(){
    Serial.begin(9600);

    // Set up stdout
    fdev_setup_stream(&serial_stdout, serial_putchar, NULL, _FDEV_SETUP_WRITE);
    stdout = &serial_stdout;

    printf("My favorite number is %6d!\n", 12);
}

void loop() {
  static long counter = 0;
  if (millis()%300==0){
    printf("millis(): %ld\tcounter: %ld (%02X)\n", millis(), counter, counter++);
    delay(1);    
  }
}