46 lines
1.1 KiB
Markdown
46 lines
1.1 KiB
Markdown
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---
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title: For Loop
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localeTitle: 对于循环
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---
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# 对于循环
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`for`循环执行代码块,直到指定的条件为false。当迭代次数可变时使用`while`循环,否则使用`for`循环。 `for`循环的常见用途是数组迭代。
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## For循环的语法
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```c
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for ( init; condition; increment ) {
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statement(s);
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}
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```
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`for`循环由3个部分组成,初始化部分,特定条件和增量或减量操作部分。这3个部分控制`for`循环。
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初始化语句只执行一次。然后,评估测试表达式。如果测试表达式为假(0),则for循环终止。但是如果测试表达式为真(非零),则执行for循环体内的代码并更新更新表达式。重复此过程直到测试表达式为假。
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当迭代次数已知时,通常使用for循环。
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## 例
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```c
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#include <stdio.h>
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int main () {
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int array[] = {1, 2, 3, 4, 5};
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for (int i = 0; i < 5; i++) {
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printf("Item on index %d is %d\n", i, array[i]);
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}
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}
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```
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## 输出:
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```shell
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> Item on index 0 is 1
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> Item on index 1 is 2
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> Item on index 2 is 3
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> Item on index 3 is 4
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```
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