Go Language Conditional Statements (if, if...else, nested if)

Decision-making in programming is similar to decision-making in real life. In decision-making, a block of code is executed when certain conditions are met. Sometimes, these are also called control flow statements.GolangUse specified statements to specify the execution flow of the program based on certain conditions. These are used to advance and branch the execution flow based on changes in the program state.

The decision-making statements in Go programming are：

• if statement

• if...else statement

• Nested if statements

• if...else...if statement

if statement

This is the simplest decision. It is used to decide whether to execute a statement or a block of statements, that is, if a certain condition isTruethen execute the statement block, otherwise do not execute.

if(condition_

if(condition)　{
　　　//The statement to be executed if
　　　//condition is true
}

Flowchart:

Example：

//Use if statements
package main
import "fmt"
func main() {
　　　　//Take a local variable
　　　　var v int =　700
　　　　//Use if statements
　　　　//Check the condition
　　　　if v <　1000 {
　　　　　　　　//Print the following content, the condition evaluation is true
　　　　　　　　fmt.Printf("v is less than1000\n")
　　　　}
　　　　fmt.Printf("The value of v is　:　%d\n", v)
}

Output:

v is less than1000
The value of v is　:　700

if…else statement

The if statement tells us that if the condition is true, it will execute the statement block, and if the condition is false, it will not execute. But what if we want to do something else when the condition is false; that's when we use the else statement. When the condition is false, we can use the else statement with the if statement to execute the code block.

if(condition_

　if(condition) {}}
　　　　//　If the condition is true, execute this code block
　　　　
}
　　　　//　If the condition is false, execute this code block
}

Flowchart:

//　Use if...else statements
package main
import "fmt"
func main() {
　　　　//Local variables
　　　　var v int =　1200
　　　　//　Use if statements to check the condition
　　　　if v <　1000 {
　　　　　　　　//Print the following content if the condition evaluates to true
　　　　　　　　fmt.Printf("v <　1000\n")
　　　　}
　　　　　　　　//Print the following content if the condition evaluates to false
　　　　　　　　fmt.Printf("v >　1000\n")
　　　　}
}

Output:

v >　1000

Nested if statements

In Go language, a nested if is an if statement that is the target of another if or else. A nested if statement is an if statement within an if statement. Yes, Golang allows us to nest if statements within if statements. We can place an if statement inside another if statement.

if(condition_

if(condition1) {
　　　//　When the condition1is true, execute
　　　
　　　if(condition2) {
　　　　　　//　When the condition2is true, execute
　　　}
}

Flowchart:

//Use nested if statements　
package main　
import "fmt"
　　
func main() {　
　　　　　　
　　　//two local variables
　　　var v1　int =　400　
　　　var v2　int =　700　
　　　
　　　//Use if statements
　　　if( v1　==　400) {　
　　　　　　　　　
　　　　　　//　If the condition is true, execute　
　　　　　　if( v2　==　700) {　
　　　　　　　　　　　　
　　　　　　　　　//　If the condition is true, execute the print output
　　　　　　　　　fmt.Printf("v1the value is400, v2the value is700\n")　
　　　　　　}　
　　　}　
　　　　
}

Output:

v1the value is400, v2the value is700

if..else..if statement

Here, the user can choose from multiple options. If statements are executed from top to bottom. Once any condition of the if is true, the associated statements will be executed, and the rest of the if statements will be skipped. If all conditions are not met, the final else statement will be executed.

Important note:

• can be 0 or1can be 0 to multiple if statements, and must be before else

• If the else if condition is true, the rest of the else if or else will not be executed

• Syntax:

if(condition_

else if(condition_1) {
　　　　　//condition_1If true, execute the following code block
}2) {
　　　　//condition_2If true, execute the following code block
}
　　　　//If no condition is true, execute the following code block
}

Flowchart:

package main　
import "fmt"
　　
func main() {　
　　　　　　
　　　var v1　int =　700　
　　　
　　　if(v1　==　100) {　
　　　　　　　　　
　　　　　　//　If the condition is true, then display the following content　
　　　　　　fmt.Printf("v1the value is100\n")　
　　　　　　　　
　　　}1　==　200) {　
　　　　　　　　　
　　　　　　fmt.Printf("v1the value is200\n")　
　　　　　　　　
　　　}1　==　300) {　
　　　　　　　　　
　　　　　　fmt.Printf("v1the value is300\n")　
　　　　　　　　
　　　}　
　　　　　　　　　
　　　　　　//if none of the conditions are true　　
　　　　　　fmt.Printf("no matching value\n")　
　　　}　
}

Output:

No matching value