if statement

流程圖
$\begin{tikzpicture}[node distance=1.5cm,auto]\setlength \baselineskip{1ex} \node [input,name=input] {}; ......$

語法

if(boolean_expression)
{
   /* statement(s) will execute if the boolean expression is true */
}

範例

[dywang@deyu zzz]$ vim if1.c
[dywang@deyu zzz]$ cat if1.c
#include <stdio.h>

int main() {
    int a;

    printf("Enter an integer: ");
    scanf("%d", &a);

    if ( a>10 ) {
		printf("%d > 10\n", a);
	}
    printf("a = %d\n", a );
}

編譯成功
```
[dywang@deyu zzz]$ gcc -o if1 if1.c
```

執行結果一

[dywang@deyu zzz]$ ./if1
Enter an integer: 3
a = 3

執行結果二

[dywang@deyu zzz]$ ./if1
Enter an integer: 13
13 > 10
a = 13