Using - C
  
 Source Code
  

    
#include<stdio.h>
#include<ctype.h>

void main() {
  char str[1024];
  int vowels=0, semi_vowels=0, consonants=0, i;	
  
    printf("Enter the String:  ");
    gets(str);
    
    for(i=0; str[i] != '\0'; i++) {
    if(toupper(str[i])=='A' || toupper(str[i])=='E' || toupper(str[i])=='I' || toupper(str[i])=='O' || toupper(str[i])=='U') {
    vowels++;			
    }
    else if(toupper(str[i])=='W' || toupper(str[i])=='Y') {
    semi_vowels++;
    }
    else if(str[i]==' ') {
      continue;
    }
    else {
    consonants++;
    }	
  }
  
  printf("\nVowels: %d\nSemi-Vowels: %d\nConsonants: %d",vowels,semi_vowels, consonants);
  
  }
    

Enter the String:  Hello World

Vowels: 3
Semi-Vowels: 1
Consonants: 6

        
Using - C++
        
 Source Code
        

        
#include<iostream>
#include<ctype.h>
using namespace std;

int main() {
  string str;
  int vowels=0, semi_vowels=0, consonants=0;	
  
    printf("Enter the String:  ");
    getline(cin,str);
    
    for(int i=0; str[i] != '\0'; i++) {
    if(toupper(str[i])=='A' || toupper(str[i])=='E' || toupper(str[i])=='I' || toupper(str[i])=='O' || toupper(str[i])=='U') {
    vowels++;			
    }
    else if(toupper(str[i])=='W' || toupper(str[i])=='Y') {
    semi_vowels++;
    }
    else if(str[i]==' ') {
      continue;
    }
    else {
    consonants++;
    }  
  }
  
  cout<< "\nVowels: "<< vowels<< "\nSemi-Vowels: "<< semi_vowels<< "\nConsonants: "<< consonants;
  return 0;
  }
      

Enter the String:  Computer Science

Vowels: 6
Semi-Vowels: 0
Consonants: 9