#include <stdio.h>
int main()
{
char line[150];
int i, vowels, consonants, digits, spaces;
vowels = consonants = digits = spaces = 0;
printf("Enter a line of string: ");
scanf("%[^\n]", 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')
{
++vowels;
}
else if((line[i]>='a'&& line[i]<='z') || (line[i]>='A'&& line[i]<='Z'))
{
++consonants;
}
else if(line[i]>='0' && line[i]<='9')
{
++digits;
}
else if (line[i]==' ')
{
++spaces;
}
}
printf("Vowels: %d",vowels);
printf("\nConsonants: %d",consonants);
printf("\nDigits: %d",digits);
printf("\nWhite spaces: %d", spaces);
return 0;
}

Output

Enter a line of string: adfslkj34 34lkj343 34lk
Vowels: 1
Consonants: 11
Digits: 9
White spaces: 2

This program takes string input from the user and stores it in a variable line.

Initially, the variables vowels, consonants, digits, and spaces are initialized to 0.

When the vowel character is found, the vowel variable is incremented by 1. Similarly, consonants, digits, and spaces are incremented when these characters are found.

Finally, the count is displayed on the screen.

C program that counts the number of vowels, consonants, digits, and spaces in a given string:

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

int main() {
    char str[100];
    int vowels = 0, consonants = 0, digits = 0, spaces = 0, i;

    printf("Enter a string: ");
    fgets(str, sizeof(str), stdin);

    for (i = 0; i < strlen(str); ++i) {
        char ch = tolower(str[i]);

        if (ch == 'a' || ch == 'e' || ch == 'i' || ch == 'o' || ch == 'u') {
            ++vowels;
        } else if (ch >= 'a' && ch <= 'z') {
            ++consonants;
        } else if (isdigit(ch)) {
            ++digits;
        } else if (ch == ' ') {
            ++spaces;
        }
    }

    printf("Vowels: %d\n", vowels);
    printf("Consonants: %d\n", consonants);
    printf("Digits: %d\n", digits);
    printf("Spaces: %d\n", spaces);

    return 0;
}

This program uses a for loop to iterate through each character in the given string. It then uses tolower() to convert the character to lowercase (so that it can be compared to lowercase vowel letters). If the character is a vowel, it increments the vowels counter. If the character is a consonant, it increments the consonants counter. If the character is a digit, it increments the digits counter. If the character is a space, it increments the spaces counter. Finally, it prints out the counts for each category.

a step-by-step explanation of a C program that counts the number of vowels and consonants in a given string:

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

int main() {
    char str[100];
    int vowels = 0, consonants = 0, i;

    printf("Enter a string: ");
    fgets(str, sizeof(str), stdin); // reads a line of text from the standard input stream

    for (i = 0; i < strlen(str); ++i) { // loop through each character in the string
        char ch = tolower(str[i]); // convert the character to lowercase to simplify the checking process

        if (ch == 'a' || ch == 'e' || ch == 'i' || ch == 'o' || ch == 'u') { // check if the character is a vowel
            ++vowels; // increment the vowel counter
        } else if (ch >= 'a' && ch <= 'z') { // check if the character is a consonant
            ++consonants; // increment the consonant counter
        }
    }

    printf("Number of vowels: %d\n", vowels); // print the number of vowels
    printf("Number of consonants: %d\n", consonants); // print the number of consonants

    return 0; // indicate successful completion of the program
}

Let’s break it down step-by-step:

1. We include the necessary header files: stdio.h for input/output functions, string.h for string handling functions, and ctype.h for character handling functions.

2. We declare a character array str of size 100 to hold the input string, and integer variables vowels and consonants to keep track of the number of vowels and consonants, respectively.

3. We prompt the user to enter a string using printf(), and read a line of text from the standard input stream using fgets(), which takes in three arguments: the character array to store the input, the size of the array, and the input stream (in this case, stdin for standard input).

4. We use a for loop to iterate through each character in the string. The loop runs from i = 0 to i < strlen(str), where strlen(str) returns the length of the string (i.e., the number of characters in the string).

5. Inside the loop, we use tolower() to convert the current character to lowercase, which simplifies the checking process.

6. We use an if statement to check if the current character is a vowel. If it is, we increment the vowels counter.

7. We use an else if statement to check if the current character is a consonant. If it is, we increment the consonants counter.

8. Once the loop is complete, we use printf() to print the number of vowels and consonants.

9. Finally, we return 0 to indicate successful completion of the program.