CSCE 206 Lab Structured Programming in C Fall 2018 Lecture 3 Luna BACKES

Today’s objective If-else logic block If - else if - else logic block switch logic block

if-else if (condition_expression) { // code to be executed if the // condition_expression is true statements; } else // code to be executed if the // condition_expression is false

Sample Code-1 #include <stdio.h> int main(void) { int a; printf("Enter a number:"); // Asks user for input scanf("%d", &a); if (a > 0) printf("%d is a positive number", a); } else printf("%d is not a positive number", a); return 0;

if-else if-else if (condition1) { // code to be executed if condition1 is true } else if (condition2) // code to be executed if condition2 is true } else if (condition3) // code to be executed if condition3 is true … else // code to be executed if all conditions are false

Sample Code-2 #include <stdio.h> int main(void) { int a; printf("Enter a number:"); // Asks user for input scanf("%d", &a); if (a>0) printf("%d is a positive number", a); } else if (a<0) printf("%d is a negative number", a); else printf("%d is zero",a); return 0;

Operators

Sample Code-3 #include <stdio.h> int main(void) { int a; printf("Enter a number:"); // Asks user for input scanf("%d", &a); if (a > 0 || a == 0) printf("%d is not a negative number", a); } else printf("%d is a negative number", a); return 0;

Nested if-else block if ( Boolean_expression1) { /* Executes when the Boolean expression 1 is true */ if ( boolean_expression2) /* Executes when the Boolean expression 2 is true */ }

Sample Code-4 #include <stdio.h> int main(void) { int a; printf("Enter a number:"); // Asks user for input scanf("%d", &a); if (a >= 0) if(a == 0) printf("%d is zero", a); } else printf("%d is a positive number", a); printf("%d is a negative number", a); return 0;

switch case

Sample Code-5 #include <stdio.h> int main(void) { int a; printf("Enter a number:"); // Asks user for input scanf("%d",&a); switch(a) case 0: printf("Zero"); break; } case 1: printf("One"); default: printf("No data"); return 0;

Now it’s your turn!

Practice Problem-1 Write a program that takes an integer as input and determines whether it is odd or even. It gives a proper sentence as output. Tips: Use if-else block

Practice Problem-2 Write a program that takes 3 integers as input and prints out the largest number of them. Tips: Use if-else if-else block

Practice Problem-3 Try Problem-1 using switch case.

Practice Problem-4 Write a C program that gets a character from the input and outputs whether the character was a vowel or a consonant.

Practice Problem-5 Write a C program that gets 3 floats from the input that represent the sides of a triangle, and outputs whether the triangle is equilateral, isosceles or scalene.

Practice Problem-6 Write a C program that gets a number (single digit) from the input and outputs the number in words. For example: Input: 3 Output: Three