1. Set a specific bit to 1: Macro #define setbit(x,y) x|=(1<<y) – Sets the y-th bit to 1.2. Set a specific bit to 0: Macro #define clrbit(x,y) x&=~(1<<y) – Sets the y-th bit to 0.3. Toggle a specific bit: Macro #define reversebit(x,y) x^=(1<<y) – Toggles the y-th bit. Note: XOR results in 0 for the … Read more
01 Given that x, y, and t are all int type variables, after executing the statement: x=y=3; t=++x||++y; the value of y is ( ) A) Undefined value B) 4 C) 3 D) 2 Answer: C Explanation: The short-circuit characteristic of || (logical OR): If the expression on the left of || is true (non-zero), … Read more
The application of modulus (<span><span>%</span></span>) and integer division (<span><span>/</span></span>) in C language. Code section: #include <stdio.h> #include <math.h> /*(Sum of Digits) Write a function that takes an integer and returns the sum of its digits. For example, given the number 7631, the function should return 17 (Explanation: 7 + 6 + 3 + 1 = … Read more
Optimizing microcontroller programs usually refers to optimizing program code or execution speed. Optimizing code and optimizing speed are actually a unified contradiction. Generally, optimizing the size of the code will lead to an increase in execution time; if the execution speed of the program is optimized, it usually results in an increase in code size. … Read more
C语言中的while循环是一种预测试循环。通常情况下，while循环允许根据给定的布尔条件执行一部分代码多次。它可以看作是一个重复的if语句。while循环主要用于在不提前知道迭代次数的情况下使用。 C语言中while循环的语法如下： while (condition) { //要执行的代码} C语言中while循环的示例以下是一个打印1的乘法表的简单while循环程序： #include <stdio.h> int main() { int i = 1; while (i <= 10) { printf("%d \n", i); i++; } return 0;} 输出： 12345678910 使用while循环打印给定数字的乘法表的程序： #include <stdio.h> int main() { int i = 1, number = 0; printf("Enter a number: "); scanf("%d", &number); while (i <= 10) { printf("%d … Read more
01 Among the following statements, the correct one is ( ) A) C language programs always start executing from the first function B) In a C language program, a function to be called must be defined within the main() function C) C language programs always start executing from the main() function D) The main() function … Read more
Defining the same function in different C source filesIn general, to maintain the simplicity and efficiency of the program, it is not recommended to define the same function (with the same return type and parameter types) in different C source files. Otherwise, the compiler may throw an error indicating multiple definitions, as shown in the … Read more
Multiple return valuesIn C language, a function can generally return only one value by default. So, how can we design a function to return two or more values?Example of a standard library functionBefore that, let’s recall a standard library function in C language that we previously introduced, ldiv(). This function can be used to perform … Read more
Today, we will explore an important concept that plays the role of a judge in programming—relational expressions. 1. Explanation of Knowledge Points 1. What is a Relational Expression? In C language, a relational expression is an expression used to compare the relationship between two values. It consists of two operands (which can be variables, constants, … Read more
