How to use conditional statement function in C++?

How to use the conditional statement function in C?

Conditional statement function is a commonly used function type in C programming, which executes different code blocks based on given conditions. Conditional statement functions include if statements, switch statements, and ternary operators, etc., which are very useful in the actual programming process. This article will introduce how to use conditional statement functions in C, as well as some common application scenarios for them.

1. If statement

The if statement is one of the most commonly used conditional statement functions in C. Its basic syntax is as follows:

if (condition) {
    // 如果条件成立，则执行这里的代码块
} else {
    // 如果条件不成立，则执行这里的代码块
}

In the if statement, condition is an expression or variable whose value is true or false. If condition is true, then the code block in the if statement is executed; if condition is false, then the code block in the else statement is executed.

The following is an example:

int num = 10;
if (num < 5) {
    cout << "num小于5" << endl;
} else {
    cout << "num大于等于5" << endl;
}

In the above example, if num is less than 5, then output "num is less than 5"; otherwise, output "num is greater than or equal to 5".

2. Switch statement

The switch statement is another commonly used conditional statement function, which is suitable for executing different code blocks based on different conditions. Its basic syntax is as follows:

switch (expression) {
    case constant1:
        // 如果expression等于constant1，则执行这里的代码块
        break;
    case constant2:
        // 如果expression等于constant2，则执行这里的代码块
        break;
    ...
    default:
        // 如果expression不等于任何一个constant，则执行这里的代码块
        break;
}

In the switch statement, expression is an expression or variable, and its value is compared with each constant. If the value of expression is equal to a certain constant value, then the corresponding code block is executed, and then the switch statement is jumped out through the break statement. If the value of expression is not equal to any constant value, then the code block in the default statement is executed.

The following is an example:

int day = 3;
switch (day) {
    case 1:
        cout << "星期一" << endl;
        break;
    case 2:
        cout << "星期二" << endl;
        break;
    case 3:
        cout << "星期三" << endl;
        break;
    default:
        cout << "其他" << endl;
        break;
}

In the above example, if the value of day is equal to 1, output "Monday"; if the value of day is equal to 2, output "Tuesday" ; If the value of day is equal to 3, output "Wednesday"; otherwise, output "Other".

3. Ternary operator

In addition to if statements and switch statements, there is also a special conditional statement function in C, the ternary operator. Its basic syntax is as follows:

condition ? expression1 : expression2

In the ternary operator, condition is an expression or variable whose value is true or false. If condition is true, the value of the entire expression is expression1; otherwise, the value of the entire expression is expression2.

The following is an example:

int num = 5;
string result = (num % 2 == 0) ? "偶数" : "奇数";
cout << result << endl;

In the above example, if num is an even number, then the value of result is "even"; if num is an odd number, then the value of result is "odd" ".

In summary, conditional statement functions are very useful in C programming. They can execute different code blocks based on given conditions. The if statement can be used to perform simple conditional judgments, the switch statement can be used to perform multiple conditional judgments, and the ternary operator can be used to implement conditional judgments in an expression. In the actual programming process, we should choose the appropriate conditional statement function to use according to specific needs. I hope this article will help readers use conditional statement functions in C programming.

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