Question

Rewrite the following program so
   that the counting of the a's and
   total count are done be
   separate functions
  
   The code you turn in should have 2 functions
*/

#include<stdio.h>

int main(void){
  
   char input[81];               // Input string
   int a=0, total=0;           // counter variables              
  
   // Ask for an input string
   puts(" Input a string of up to 80 characters and\n"
   " I will tell you how many a\'s it contains \n"
   " as well as a total character count.\n\n");
  
   fputs(" ",stdout);               // just make things line up

   // read the input string
   fgets(input,80,stdin);

   while(input[total] != '\0'){                       // go through the string

       if(input[total] == 'a' || input[total] == 'A')   // count the number of a's
           a++;

       total++;                       // total character count
   }
  
   total--;                           // fgets reads the newline - we don't want to count that
  
   // output the results
   printf(" %d a\'s and %d total characters.\n",a,total);
  
   return 0;
}

Answer 1

We have to rewrite given program so that counting of a's and total count are done in different functions.

So we will create a function named count_a() which will take input string as parameter and return number of a's .

We will create another function named count_total() which will also take input string as parameter and return total number of characters present in string.

Modified program-

#include<stdio.h>

//function to find number of a in string
int count_a(char input[]){
    int i=0;
    int a=0;
    while(input[i] != '\0'){     //traverse whole string till we reach the end
        if(input[i]=='a' || input[i]=='A'){
            a++;               // if character is 'a' then we will increase the count of a
        }
        i++;                  //increment i to reach to next element of string
    }
    return a;                //return taotal number of a's in the string
}

//function to find total number of characters in string
int count_total(char input[]){
    int total=0;
    
    while(input[total] != '\0'){          //traverse whole string till we reach end of string
        total++;                          //total characters count
    }
    total--;                              //fgets reads the newline - we don't want to count that
    return total;                        //return total number of characters
}

int main(void){
  
   char input[81];               // Input string
   int a, total;           // counter variables              
  
   // Ask for an input string
   puts(" Input a string of up to 80 characters and\n"
   " I will tell you how many a\'s it contains \n"
   " as well as a total character count.\n\n");
  
   fputs(" ",stdout);               // just make things line up

   // read the input string
   fgets(input,80,stdin);

   a=count_a(input);                //calling the function to count a's
   
   total=count_total(input);        // calling the function to count total characters
  
   // output the results
   printf(" %d a\'s and %d total characters.\n",a,total);
  
   return 0;
}

Comments are added in the program for better understanding.