Question

What I want to do is reverse a string of numbers that the user enters. what happens is it compiles and runs till i hit enter after the scanf. then I get some Microsoft runtime error… what’s going wrong???

NOTE: this is homework, but i’ve got the logic figured out. what baffles me is this error.

#include <stdio.h>
int main()
{
    unsigned int giveStr = 0;
    char* charIt;
    printf("Enter a number to be reversed.\t");
    scanf("%d", &giveStr);
    fflush(stdin);
    sprintf(charIt, "%d", giveStr);
    revStr(giveStr);
    getchar();
    return 0;
}

revStr(unsigned int n)
{
      char buffer[100];
      int uselessvar, counter = 0;
      for (; n > 0;)
      {
           uselessvar = sprintf(&buffer[counter], "%d", n);
           counter++;
      }
      for (counter = 0; counter > 0;)
      {
          printf("%c", buffer[counter]);
          counter--;
      }
      return 0;
}

EDIT: flushing stdin for newlines :/ and also image here just not with that program. with mine.

Answer 1

For your home work problem, if you have the K&R book, turn to section 3.5 and read it thoroughly.

Note the functions reverse() and itoa(). They should give you a pretty good idea on how to solve your problem.