Question

III. Answer part A,B, and C. (in JAVA)

3a)

Return the number of times the letter 'a' occurs in a String.

countA("abc") → 1
countA("wxyz") → 0
countA("bcaca") → 2

3b)

Return the number of times the given letter ch occurs in the given String str.

countNumChar("abc", "a") → 1
countNumChar("wxyz", "b") → 0
countNumChar("bcaca", "c") → 2

3c)

Count the number of characters that are either a or b in a String. Try to use only one for loop.

countAorB("abc") → 2
countAorB("xyz") → 0
countAorB("ab") → 2

Answer 1

public class Main{
        // it counts number of a
        public int countA(String s){
                int i, count=0;
                for(i=0;i<s.length();i++){
                        if(s.charAt(i)=='a')
                                count++;
                }
                return count;
        }
        
        // it counts number of a charater 
        public int countNumChar(String s, char x){
                int i, count=0;
                for(i=0;i<s.length();i++){
                        if(s.charAt(i)==x)
                                count++;
                }
                return count;
        }
        
        // it counts chracters either a or b
        public int countAorB(String s){
                int i, count=0;
                for(i=0;i<s.length();i++){
                        if(s.charAt(i)=='a'|| s.charAt(i)=='b')
                                count++;
                }
                return count;
        }
        
        
        public static void main(String args[]){
                // declare object of class
                Main obj=new Main();
                
                // call the functions and display the result
                System.out.println("Number of `a' in "+"abc"+" is: "+obj.countA("abc"));
                System.out.println("Number of `a' in "+"wxyz"+" is: "+obj.countA("wxyz"));
                System.out.println("Number of `a' in "+"bcaca"+" is: "+obj.countA("bcaca")+"\n");
                
                System.out.println("Number of `a' in "+"abc"+" is: "+obj.countNumChar("abc",'a'));
                System.out.println("Number of `b' in "+"wxyz"+" is: "+obj.countNumChar("wxyz",'b'));
                System.out.println("Number of `c' in "+"bcaca"+" is: "+obj.countNumChar("bcaca",'c')+"\n");
                
                System.out.println("Number of `a' or `b' in "+"abc"+" is: "+obj.countAorB("abc"));
                System.out.println("Number of `a' or `b' in "+"xyz"+" is: "+obj.countAorB("xyz"));
                System.out.println("Number of `a' or `b' in "+"ab"+" is: "+obj.countAorB("ab"));
        }
}

___________________________________________________________________

Number of `a' in abc is: 1
Number of `a' in wxyz is: 0
Number of `a' in bcaca is: 2

Number of `a' in abc is: 1
Number of `b' in wxyz is: 0
Number of `c' in bcaca is: 2

Number of `a' or `b' in abc is: 2
Number of `a' or `b' in xyz is: 0
Number of `a' or `b' in ab is: 2

___________________________________________________________________

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