后面这个语句只有 x 是 10 时才为真,而前面赋值的那个语句则永远为真。 这是因为 C 语言按以下规则进行运算 if (x=10):10 赋值给 x(只要非 0 的数赋值的语句,其赋值表达式的值永远为真),因此 x 现在值为 10。此时 if 的测试表达式值为 10,该值永远为真,因为非 0 值永远为真。所以,if (x = 10...
the function code requested, the message data and length of it,//plus a user-supplied token to identify the causing requestvoidhandleData(ModbusMessage response, uint32_t token) {//回调函数Serial.printf("Response: serverID=%d, FC=%d, Token=%08X, length=%d:...
11.14 String object( String类) 11.15 array(数组) 十二、数据类型转换 12.1 char() 12.2 byte() 12.3int() 12.4 word() 12.5 long() 12.6 float() 十三、变量作用域&修饰符 13.1 variable scope(变量的作用域) 13.2 static(静态变量) 13.3 volatile 13.4 const 十四、辅助工具 14.1sizeof() 函数部分 十五...
a block (array of bytes to the I2C device and register @param[in] reg the register in the I2C device to write to @param[in] val pointer to the beginning of the data byte array @param[in] len the length (in bytes) of the data to write @return True if successful write operation. ...
("String length is: "); Serial.println(num); // (3) get the length of the array (includes null terminator) num = sizeof(str); // sizeof() is not a C string function Serial.print("Size of the array: "); Serial.println(num); // (4) copy a string strcpy(out_str, str); ...
//Compute average of a int array, given the starting pointer and the length int compute_average(int *avgs, int len) { int sum = 0; for (int i = 0; i < len; i++) sum += avgs[i]; return (int)(sum / len); } //Insert a value into an array, and shift it down removing...
函数String charAt() compareTo() concat() endsWith() equals() equalsIgnoreCase() GetBytes() indexOf() lastIndexOf length replace() setCharAt() startsWith() substring() toCharArray() toLowerCase() toUpperCase() trim() 操作符 [](元素访问) +(串连) ==(比较) array Arrays (数组) 数组是一...
extractLetters(morseCode.substring(startPos1, endPos1)); // This function would extract Letter as name suggest and would convert code to text SIMPLE! startPos1 = endPos1 + 1; if (startPos1 == morseCode.length()) { break; } endPos1 = morseCode.indexOf('#', startPos1); ...
my_device.set_dp_cmd_total(dp_array, 1); //dp_array:为存储DP点ID和数据类型的数组, 1:为数组内定义的DP个数 ... } 初始化时还需注册DP点下发处理函数和上传所有DP点函数: unsigned char led_state = 0; void setup() { ... //register DP download processing callback function ...
len should give the maximum dimensions of the array and is used to avoid buffer overflows. void setWriteCal(uint8_t channel,float* coeff,uint8_t len) This method sets a polynomial for the given channel used by the writeCal method. The coefficients should be an array of length len given...