C Decision Making Programs | 10+ Examples

In this article, after going through all the fundamentals of C programming languages we will learn C decision making programs with examples.

Do not forget that the best way of learning programming is by practice and developing your concept.

c decision making program flow chart

1 WAP to input two numbers & print the greatest.

#include <stdio.h>
int main()
{
    int n, m;
    // Asking user to enter the two numbers
    printf("Please Enter Two different values\n");
    // Accepting two numbers
    scanf("%d %d", &n, &m);
    if(n > m)
    {
        printf("%d is Largest\n", n);
    }
    else if (m > n)
    {
        printf("%d is Largest\n", m);
    }
    else
    {
        printf("Both are Equal\n");
    }
    return 0;
}

Output

Please Enter Two different values
8
6
8 is Largest

We can write the same program using conditional operator (ternary operator)

#include <stdio.h>
int main()
{
    int n, m;
    // Asking user to enter the two numbers
    printf("Please Enter Two different values\n");
    // Read two numbers from the user
    scanf("%d %d", &n, &m);
    (n >= m)?((n ==m)?printf("Numbers are equal"):printf("%d is Largest\n", n)):printf("%d is Largest\n", m);
    return 0;
}

Output

Please Enter Two different values
7
8
8 is Largest

2 WAP to find the largest out of three numbers.

Let’s write the steps involved in the program sequentially.

  • Firstly we will ask user to enter three integer values.
  • Entered value will be stored in the three integer values in num1, num2, and num3
  • Compare the number and check if num1 is greater than num2.
  • If true, then we will check if num1 is greater than num3.
    • If true, then print ‘num1’ as the greatest number.
    • If false, then print ‘num3’ as the greatest number.
  • If false, then we will check if num2 is greater than num3.
    • If true, then print ‘num2’ as the greatest number.
    • If false, then print ‘num3’ as the greatest number.

Program

#include <stdio.h>
int main()
{
    int p, q, r;
    printf(" Enter the number1 = ");
    scanf("%d", &p);
    printf("\n Enter the number2 = ");
    scanf("%d", &q);
    printf("\n Enter the number3 = ");
    scanf("%d", &r);
    if (p > q)
    {
        if (p > r)
        {
            printf("\n Largest number = %d \n",p);
        }
        else
        {
            printf("\n Largest number = %d \n",r);
        }
    }
    else if (q > r)
    {
        printf("\n Largest number = %d \n",q);
    }
    else
    {
        printf("\n Largest number = %d \n",r);
    }
    return 0;
}

Output

Enter the number1 = 6
Enter the number2 = 9
Enter the number3 = 5
Largest number = 9

3 WAP to check if the year is a leap year or not

leap year program in c

Flow chart for checking leap year

C Decision Making Programs | 10+ Examples
Img src: Internet

Program to check year is a leap year or not

#include <stdio.h>
int main()
{
   int year;
   printf("Enter a year: ");
   scanf("%d", &year);

   // leap year if perfectly divisible by 400
   if (year % 400 == 0) {
      printf("%d is a leap year.", year);
   }
   // not a leap year if divisible by 100
   // but not divisible by 400
   else if (year % 100 == 0) {
      printf("%d is not a leap year.", year);
   }
   // leap year if not divisible by 100
   // but divisible by 4
   else if (year % 4 == 0) {
      printf("%d is a leap year.", year);
   }
   // all other years are not leap years
   else {
      printf("%d is not a leap year.", year);
   }

   return 0;
}

Output

//Output-1
Enter a year: 2020
2020 is a leap year.

//Output-2
Enter a year: 2019
2019 is not a leap year.

4 WAP to input a character and print its next character.

Ex. If the character entered is ‘a’, display “The next character is b”.

#include <stdio.h>
int main()
{
    char ch;
    printf("Enter a character:\t");
    scanf("%c", &ch);
    printf("You entered: %c\n", ch);
    printf("Next character: %c\n", ch + 1);
}

Output

Enter a character: B
You entered: B
Next character: C

5 WAP to input a character and print its previous character.

Ex. If the character entered is ‘b’, display “The previous character is a”.

#include <stdio.h>
int main()
{
    char ch;
    printf("Enter a character:\t");
    scanf("%c", &ch);
    printf("You entered: %c\n", ch);
    printf("Previous character: %c\n", ch - 1);
}

Output

Enter a character:	K
You entered: K
Previous character: J

6 WAP to input a character and check if it is in lower case or upper case.

ASCII Values A-65 Z-90 ; a-97 z-122. Click here for ASCII Table

There are 2 ways of writing this program

Method-1

#include<stdio.h>

int main() {
   char ch;

   printf("\nEnter The Character : ");
   scanf("%c", &ch);

   if (ch >= 65 && ch <= 90)
      printf("Character is Upper Case Letters");
   else
      printf("Character is Not Upper Case Letters");

   return (0);
}

Method-2

#include<stdio.h>

int main() {
   char ch;

   printf("\nEnter The Character : ");
   scanf("%c", &ch);

   if (ch >= 'A' && ch <= 'Z')
      printf("Character is Upper Case Letters");
   else
      printf("Character is Not Upper Case Letters");

   return (0);
}

Output

Enter The Character : A
Character is Uppercase Letters

Do not forget to execute the program here by changing the logic and values to see the different outputs in order to have a better understanding of the program.

7 WAP to input a character and change its case.

#include<stdio.h>

int main()
{
    char ch;
    printf("Enter any character : ");
    scanf("%ch", &ch);
    if(ch>='A' && ch<='Z')
        ch=ch+32;
    else if(ch>'a' && ch<='z')
        ch=ch-32;
    printf("Convert case of character : %c",ch);
    return 0;
}

Output

Enter any character : D
Convert case of character : d

8 WAP to input a character and check if it is a vowel or a consonant.

#include <stdio.h>

int main()
{
    char ch;

    printf("Please Enter an alphabet: \n");
    scanf(" %c", &ch);
    
    if(ch == 'a' || ch == 'e' || ch == 'i' || ch == 'o' || ch == 'u' ||    
       ch == 'A' || ch == 'E' || ch == 'I' || ch == 'O' || ch == 'U')
    {
        printf("\n %c is a VOWEL.", ch);
    }
    else
    {
        printf("\n %c is a CONSONANT.", ch);
    }
    return 0;
}

Output

Please Enter an alphabet: 
e
e is a VOWEL.

9 WAP to find the average of six subjects and display the results as follows

AVERAGERESULT
>34 & <50Third Division
>50& <60Second Division
>60& <75First Division
>75& <100Distinction
If marks in any subject less than 35Fail
#include <stdio.h>

int main()
{
    float marks1, marks2, marks3, marks4, marks5, marks6, avg;

    printf("Enter marks obtained in subject 1 :");
    scanf("%f", &marks1);
    printf("Enter marks obtained in subject 2 :");
    scanf("%f", &marks2);
    printf("Enter marks obtained in subject 3 :");
    scanf("%f", &marks3);
    printf("Enter marks obtained in subject 4 :");
    scanf("%f", &marks4);
    printf("Enter marks obtained in subject 5 :");
    scanf("%f", &marks5);
    printf("Enter marks obtained in subject 6 :");
    scanf("%f", &marks6);

    avg = (marks1 + marks2 + marks3 + marks4 + marks5 + marks6) / 6;
    printf("avg : %0.2f\n", avg);

    if (avg > 75)
    {
        printf("Distinction");
    }
    else if (avg > 60 && avg <= 75)
    {
        printf("First Division");
    }
    else if (avg > 50 && avg <= 60)
    {
        printf("Second Division");
    }
    else if (avg > 34 && avg <= 50)
    {
        printf("Grade D");
    }
    else
    {
        printf("Grade F");
    }

    return 0;
}

Output

Enter marks obtained in subject 1 :85
Enter marks obtained in subject 2 :85
Enter marks obtained in subject 3 :85
Enter marks obtained in subject 4 :85
Enter marks obtained in subject 5 :85
Enter marks obtained in subject 6 :85
avg : 85.00
Distinction

10 WAP to input a character and to print whether a given character is an alphabet, digit or any other character.

#include<stdio.h>
int main()
{
    char ch;
    printf("\nEnter Any Character :");
    scanf("%c",&ch);
    if(ch>='0' && ch<='9')
    { 
        printf("\n Entered Character is Digit");
    }
    else 
        if(ch>='A' && ch<='Z')
        {
            printf("\n Entered Character is Capital Letter Alphabet");
        }
        else if(ch>='a' && ch<='z')
        {
            printf("\n Entered Character is Small Letter Alphabet");
        }
        else
          printf("\n Entered Character is Special Character");
    return 0;
}

Output

Enter Any Character :@
Entered Character is Special Character

Enter Any Character :d
Entered Character is Small Letter Alphabet

Enter Any Character :A
Entered Character is Capital Letter Alphabet

Above are some basic questions asked in classes related to c decision making programs.

Do not forget to execute the program here by changing the logic and values to see the different outputs in order to have a better understanding of the program.

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