在一行C上将字符串的各个字符转换为ASCII值

Question

keep in mind i'm a complete beginner and i'm still getting acclimated to the programming vocabulary.

When I run the debug from visual studio, the command prompt comes up with "Enter any string: " but when I enter something, i get "Exception thrown blah blah blah". What is going wrong? Any help and criticism is greatly appreciated. I've been losing my mind over this for 4 hours now.

Heres my code:

int main(){

    char str[100];
    int i=0;

    printf("Enter any string: ");
    scanf_s("%s",str);

    printf("ASCII values of each characters of given string: ");
    while(str[i])
         printf("%d ",str[i++]);


    return 0;
}

Answer 1

The scanf_s() function must be used with a third argument to indicate the max length of the string ie scanf_s("%s", str, 100);

BTW scanf_s() is specific to Microsoft Visual Studio so it's less portable so I don't recommend it and str isn't a really good variable name

Answer 2

The posted code is:

1. not portable
2. contains 'magic' (not basis for value) numbers
3. spreads the variable i declaration far from its' usage
4. will not input past a 'white space' character

The following code corrects those problems, checks for errors, and compiles cleanly

#include <stdio.h>   // scanf(), printf(), perror()
#include <stdlib.h>  // exit(), EXIT_FAILURE

#define MAX_STR_LEN (100)

int main( void )
{

    char str[ MAX_STR_LEN ];

    printf("Enter any string: ");
    if( NULL == fgets( str, sizeof(str), stdin ))
    {
        perror( "fgets failed" );
        exit( EXIT_FAILURE );
    }

    // implied else, scanf successful

    printf("ASCII values of each characters of given string: ");
    for( size_t i=0; str[i]; i++ )
         printf("%d ",str[i]);


    return 0;
}

Note: the above code will input the newline and print it (10 on linux) You might want to use something to eliminate the newline, so insert the following, right after the call to fgets() :

char *newline = NULL;
if( NULL != ( newline = strstr( str, "\n" ) ) )
{ // carriage return found
    *newline = '\0';
}

This method of eliminating the newline char means the code also needs:

#include <string.h> // strstr()