"String index our of range"

Question

Trying to run this code ends with "string index out of range" error. What is wrong with it?

num_str = input()
n = len(num_str)
i = 0
sum = 0
while i<n:
    i=i+1
    a=int(num_str[i])
mean = sum / n

Answer 1

num_str = input()
n = len(num_str)
i = 0
sum = 0
while i<n-1:
    i=i+1
    a=int(num_str[i])
mean = sum / n

Answer 2

change line 2 as

n = len(num_str)-1

since array indexing starts from 0..Therefore the last element will be present at index (n-1) and if you try to access element n it gives you an error

Answer 3

I am not exactly sure what you are trying to compute, but I have tried to write a relatively clear C code of what you might have been trying to do above.

I have included certain "printf" statements for you to check few validations.

/******************************************************************************

                            Online C Compiler.
                Code, Compile, Run and Debug C program online.
Write your code in this editor and press "Run" button to compile and execute it.

*******************************************************************************/

#include <stdio.h>
#include <string.h>
int main()
{
    printf("Hello World\n");
    
    //num_str = input();
    char num_str[30];
    printf("Enter a string: ");
    scanf("%s",num_str);
    
    int n =0 ;
    n = strlen(num_str);
    printf("strlen: %d\n",n);
    int i = 0;
    int sum = 0;
    int a;
    while (i<n)
    {
        i=i+1;
        a=(int)(num_str[i]);
    }    
    int mean = sum / n;
    
    printf("Mean value: %d",mean);

    return 0;
}