C program for String Reversal | Samsung

C program for String Reversal | Samsung


Write a C program for String Reversal. Print it in a reverse manner eliminating the repeated characters and spaces.



  • Get the String from the user and reverse the string.
  • Check for the repeated characters using checkRepeat function.
  • If the element is already present skip that character or else store it in new array.
  • If the element is empty space then skip that character.
  • Print the new array.


//C doesn't support bool so we convert int as bool by using typedef
typedef int bool;
#define true 1
#define false 0
bool checkRepeat(char arr[],int find)
    int i, len = strlen(arr);
    bool flag = false;
    for(i = 0; i< len ; i++)
        if( find == arr[i])
             flag = true;           //Variable already present in array

    return flag;
int main()
    char arr[20],arr2[20], ch;
    bool flag;
    //don't use scanf("%s",&arr) cuz it stops when encounter a space
    int i,j,len = strlen(arr);
     j = len-1;
     /*Reversing the string*/
    for(i = 0;i< len/2; i++)
        ch = arr[i];
        arr[i] = arr[j];
        arr[j] = ch;
    arr2[0] = arr[0];
    j = 1;
    for(i = 1; i<len; i++)
        if(arr[i] == ' ')
            continue;                   //Skip if space
        flag = checkRepeat(arr2, arr[i]);
        if(!flag)                       //If not a repeating variable
            arr2[j] = arr[i];

    printf("\n%s", arr2);
    return 0;



Time complexity is O(n), here n is the length of the input.

Space complexity is O(n), here n is the length of the input.

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