program 31: reversing a string

The need:
     This program in some places we need to reverse the given string like in next post (binary conversion). This program asks the user for a string, reverses that and prints back.

The code: 
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#include<stdio.h>
#include<string.h>
main()
{
    int i=0,length;
    char c,str[50];
    printf("Enter a string => ");
    gets(str);
    length=strlen(str);
    for(i=0;i<length/2;i++)
    {
      c=str[i];
      str[i]= str[length-1-i];
      str[length-1-i]=c;
    }
    printf("\nreversed string is => ");
    puts(str);
    getchar();
}

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The approach:     

    There are many ways to reverse a string. Here I have exchanged last character with first, second with second last and so on up to middle of string.