Find the Number of Vowels, Consonants, Digits and White space in a String in C Program

This program takes a string from user and finds the total number of vowels, consonants, digits and white space present in that string.

Source Code to Find Number of Vowels, Consonants, Digits and White Space Character

#include<stdio.h>
int main(){
    char line[150];
    int i,v,c,ch,d,s,o;
    o=v=c=ch=d=s=0;
    printf("Enter a line of string:\n");
    gets(line);
    for(i=0;line[i]!='\0';++i)
    {
        if(line[i]=='a' || line[i]=='e' || line[i]=='i' || line[i]=='o' || line[i]=='u' || line[i]=='A' || line[i]=='E' || line[i]=='I' || line[i]=='O' || line[i]=='U')
            ++v;
        else if((line[i]>='a'&& line[i]<='z') || (line[i]>='A'&& line[i]<='Z'))
            ++c;
        else if(line[i]>='0'&&c<='9')
            ++d;
        else if (line[i]==' ')
            ++s;
    }
    printf("Vowels: %d",v);
    printf("\nConsonants: %d",c);
    printf("\nDigits: %d",d);
    printf("\nWhite spaces: %d",s);
    return 0;
}

Output

Enter a line of string:
This program is easy 2 understand
Vowels: 9
Consonants: 18
Digits: 1
White spaces: 5