C Program to Store Information(name, roll and marks) of a Student Using Structure

#include <stdio.h>
struct student
{
    char name[50];
    int roll;
    float marks;
} s;

int main()
{
    printf("Enter information:\n");

    printf("Enter name: ");
    scanf("%s", s.name);

    printf("Enter roll number: ");
    scanf("%d", &s.roll);

    printf("Enter marks: ");
    scanf("%f", &s.marks);


    printf("Displaying Information:\n");

    printf("Name: ");
    puts(s.name);

    printf("Roll number: %d\n",s.roll);

    printf("Marks: %.1f\n", s.marks);

    return 0;
}

Output

Enter information:
Enter name: Jack
Enter roll number: 23
Enter marks: 34.5
Displaying Information:
Name: Jack
Roll number: 23
Marks: 34.5

C Program to Sort Elements in Lexicographical Order (Dictionary Order)

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

int main()
{
    int i, j;
    char str[10][50], temp[50];

    printf("Enter 10 words:\n");

    for(i=0; i<10; ++i)
        scanf("%s[^\n]",str[i]);


    for(i=0; i<9; ++i)
        for(j=i+1; j<10 ; ++j)
        {
            if(strcmp(str[i], str[j])>0)
            {
                strcpy(temp, str[i]);
                strcpy(str[i], str[j]);
                strcpy(str[j], temp);
            }
        }

    printf("\nIn lexicographical order: \n");
    for(i=0; i<10; ++i)
    {
        puts(str[i]);
    }

    return 0;
}

Output

Enter 10 words:
C
C++
Java
PHP
Python
Perl
Ruby
R
JavaScript
PHP

In lexicographical order: 
C
C++
Java
JavaScript
PHP
PHP
Perl
Python
R
Ruby

C Program to Copy String Without Using strcpy()

#include <stdio.h>
int main()
{
    char s1[100], s2[100], i;

    printf("Enter string s1: ");
    scanf("%s",s1);

    for(i = 0; s1[i] != '\0'; ++i)
    {
        s2[i] = s1[i];
    }

    s2[i] = '\0';
    printf("String s2: %s", s2);

    return 0;
}

Output

Enter String s1: programiz 
String s2: programiz

C Program to Concatenate Two Strings

#include <stdio.h>
int main()
{
    char s1[100], s2[100], i, j;

    printf("Enter first string: ");
    scanf("%s", s1);

    printf("Enter second string: ");
    scanf("%s", s2);

    // calculate the length of string s1
    // and store it in i
    for(i = 0; s1[i] != '\0'; ++i);

    for(j = 0; s2[j] != '\0'; ++j, ++i)
    {
        s1[i] = s2[j];
    }

    s1[i] = '\0';
    printf("After concatenation: %s", s1);

    return 0;
}

Output

Enter first string: lol
Enter second string: :)
After concatenation: lol:)

C Program to Find the Length of a String

#include <stdio.h>
int main()
{
    char s[1000], i;

    printf("Enter a string: ");
    scanf("%s", s);

    for(i = 0; s[i] != '\0'; ++i);

    printf("Length of string: %d", i);
    return 0;
}

Output

Enter a string: Programiz
Length of string: 9

C Program to Remove all Characters in a String Except Alphabet

#include<stdio.h>

int main()
{
    char line[150];
    int i, j;
    printf("Enter a string: ");
    gets(line);

    for(i = 0; line[i] != '\0'; ++i)
    {
        while (!( (line[i] >= 'a' && line[i] <= 'z') || (line[i] >= 'A' && line[i] <= 'Z') || line[i] == '\0') )
        {
            for(j = i; line[j] != '\0'; ++j)
            {
                line[j] = line[j+1];
            }
            line[j] = '\0';
        }
    }
    printf("Output String: ");
    puts(line);
    return 0;
}

Output

Enter a string: p2'r-o@gram84iz./
Output String: programiz

C program to count the number of vowels, consonants and so on

#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