62 lines
1.2 KiB
Markdown
62 lines
1.2 KiB
Markdown
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---
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title: If
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localeTitle: 如果
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---
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# 如果
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if语句根据条件执行不同的代码块。
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```
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if (condition) {
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// Do something when `condition` is true
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}
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else {
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// Do something when `condition` is false
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}
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```
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当`condition`为真，代码里面`if`部分执行，否则`else`执行。有时您需要添加第二个条件。为了便于阅读，您应该使用`else if`而不是嵌套`if`语句。
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```
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if (condition) {
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// Do something if `condition` is true
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}
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else if (anotherCondition) {
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// Do something if `anotherCondition` is ture
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}
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else {
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// Do something if `condition` AND `anotherCondition` is false
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}
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```
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请注意， `else`和`else if`部分不是必需的，而`if`是必需的。
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## 例
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```
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#include <stdio.h>
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int main () {
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// Local variable definition
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int a = 10;
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// Check the boolean condition
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if(a < 5) {
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// If condition is true then print the following
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printf("a is less than 5!\n" );
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}
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else {
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// If condition is false then print the following
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printf("a is not less than 5!\n" );
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}
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printf("Value of a is : %d\n", a);
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return 0;
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}
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```
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## 产量
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```
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-> a is not less than 5!
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-> Value of a is : 100
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```
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