Question

What to do

This assignment will give you some exposure to how strings are implemented in C. Please create one file main.c that contains a driver main() and a function str_len() as follows:

• int main(void);
• int str_len(char string[]);

Here is what these functions are supposed to do:

• main() is the driver that calls str_len(). Specifically, main() will take a string from the command line and print out the length of the string, internally using str_len().
• str_len() takes one arguments, i.e. a string of some sort and returns the length of the string, i.e. the number of characters that the string contains (excluding the ASCII zero at the end of the string). Your code will need to run through the whole string, char by char. I want you to do this is four distinctly different ways, i.e. using two for loops and two while loops (we did this in class, so refer to your notes). As you will want to have only one of the four options working at a specific time, I ask you to comment out the other three options in your code submission.

What to submit

I ask you to submit, here on BBLearn, on or before the due date:

• Your code file main.c
• A screen shot of a run of your driver when you input the string "hello world!".

Hints

Don't let yourself get confused about the string length your function returns, when you have it work on a string that was taken from the command line. Depending on the function that you use to capture the string, it may contain the new line character at its very end

Answer 1

#include<stdio.h>
int str_len(char *s){
int count=0;//this will be a part of every method
//method 1 using for loop and comparing to '\0' (null character which is till by default at the end of string)
for(count=0;s[count]!='\0';count++);
return count;
/* //method 2 using for loop and comparing to 0(which is ASCII value of null character)
for(count=0;s[count]!=0;count++);
return count;
*/

/* //method 3 using while loop and comparing to '\0'
while(s[count]!='\0')
  count++;
return count;
*/

/* //method 4 using while loop and comparing to 0
while(s[count]!=0)
  count++;
return count;
*/
}

int main(void){
printf("Enter String:");
char str[50];
scanf("%[^\n]%*c",str); //%[^\n]%*c - this reads till a new line character is given as input and removes it from the input
printf("Length of string is:%d",str_len(str));
}

//please comment in case of any doubt