- #include <stdio.h> 
- #include <string.h> 
-   
- void reverse(char str[]) { 
-     char tmp; 
-     for (int i = len / 2; i >= 0; i--) { 
-         tmp = str[i]; 
-         str[i] = str[len - i - 1]; 
-         str[len - i - 1] = tmp; 
-     } 
- } 
-   
- int main(void) { 
- 	char str[] = "123"; 
- 	reverse(str); 
- } 
-   
- //https://pt.stackoverflow.com/q/37031/101 
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