Function and Pointer Interaction

Question

I am VERY new to C programming. I have a function which will take a pointer to a string as input and print the reverse of that string. When I invoke that function in the main method, it outputs junk. I think it might be a problem with how I am using pointers.

My code is:

    #include <stdio.h>
    #include <stdlib.h>
    #include <string.h>

    #define MAX_LEN 100

    void reverse(char* str)
    {
        int i, j;
        int temp;
        int length;
        length = strlen(str);
        i= 0;
        j=(length-1);
        while (i<j){
          temp=str[i];
          str[i] = str[j];
          str[j]=temp;
          i++;
          j--;
       }
        printf("Your reversed string is: ");
        for (i=0; i<length; i++){
          printf("%d", str[i]);
       }
       printf("\n");
    }

int main()
    {
        char mystring[MAX_LEN+1];
        printf("Enter the string. \n");
        scanf("%s", mystring);
        printf("%s", mystring);
        printf("\n");
       reverse(mystring);
    }

and the output is:

Enter the string.
help
help
Your reversed string is: 112108101104

user2736738 · Accepted Answer · 2017-12-08 18:03:38Z

4

printf("%c", str[i]); You printed the ascii values earlier. Use %c specifier to print the characters.

For example, you can see that in ascii-chart

112 108 101 104
 p   l   e    h

Or even more easily you could have done this

printf("%s",str);

edited Dec 8, 2017 at 18:03

answered Dec 8, 2017 at 18:00

user2736738

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