Here is a program to count number of vowels present in an entered sentence.
Logic: Here variable ‘vowels’ is incremented whenever a vowel found in tracing. Logic behind this is very simple, that comparing each character to the set of vowels, predefined in an array. If this character is in the set of vowels then it implies that character is a vowel, so we increment the count by one.
Same logic can be applied to find the existence of any letter set in the predetermined array.
#include<stdio.h>
#include<conio.h>
void main()
{
char str[50];
int vowels = 0, i = 0;
clrscr();
printf(“nnt ENTER A STRING…: “);
gets(str);
while(str[i] != ‘