Clue what is stopping the program to reach and execute: string s = get_string(“plaintext: “)

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#include<stdio.h>
#include<cs50.h>
#include<string.h>
#include<ctype.h>
#include<stdlib.h>
int main(int argc, string argv[])
{
int counter = 0;
    if (argc != 2)
    {
    return 1;
    }
string key = argv[1];
int t = strlen(key);
    if(t != 26)
    {
    return 1;
    }
    while(counter < t)
    {
    isdigit (argv[1][counter]);
    return 1;
    counter = counter + 1;
    }
string s = get_string("plaintext: ");
int countstring = strlen(s);//count the number of characters entered by the user as plaintext
    for(int i = 0; i <= countstring; i++)//starts with first character of plaintext till the end
    {
        if (isalpha (s))//if character is alphabetic
        {
        s= argv[1];//replace index value of alphabetic character with the same position of key array
        }
        else
        {
       s = s;//if not alphabetic, then the entered character remains the same
        }
    }
printf("ciphertext: %s",s);
}

			

 

While I do understand that there is a lot more to do to meet the project’s requirements, still not sure why the above program though compiling fails to give any clue if I have made any progress. I just get $ prompt whatever I enter after ./substitution.

To be specific, what is stopping the program to reach and execute:

string s = get_string(“plaintext: “);

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while(counter < t)
{
    isdigit (argv[1][counter]);   // Evaluates to true or false
    return 1;                     // Always executes
    counter = counter + 1;
}

			

 

n your while loop the value of isdigit() is not used, a true or false is just “sitting” there on the line. The “return 1” is always executed since there is no condition if the return should execute or not. You most likely meant to condition the “return” on the result of the isdigit() check 🙂

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Query

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Thanks for pointing it out. Here is how I revised:

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while(counter < t)
{
    if (isdigit (argv[1][counter]))
    {
    return 1;
    }
    else
    {
    counter = counter + 1;
    }
}

			

 

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Much better! Only thing is that you are only checking for digits, what you should be checking is non-alphabetic 🙂[learn_press_profile]

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