C Programming Language Part 9
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The document contains 5 code snippets demonstrating the use of various C functions: 1) A program that calculates the sum of 1/n from n=1 to 10 using a cast to convert n to a float. 2) A program that gets a single character input and prints a message based on the input. 3) A program that tests if a character is a letter, digit or other character using isalpha and isdigit functions. 4) A program that converts a character to uppercase if lowercase and vice versa using islower, toupper, tolower. 5) A program that converts a character to lowercase if uppercase and vice versa using isupper, tolower, toupper.
C Programming Language Part 9
- 2. #include <stdio.h> main() { float sum ; int n ; sum = 0 ; for( n = 1 ; n <= 10 ; ++n ) { sum = sum + 1/(float)n ; printf("%2d %6.4fn", n, sum) ; } } PROGRAM SHOWING THE USE OF A CAST
- 3. The program in shows the use of getchar function in an interactive environment. The program displays a question of YES/NO type to the user and reads the user's response in a single character (Y or N). If the response is Y, it outputs the message My name is BUSY BEE otherwise, outputs. You are good for nothing
- 4. #include<stdio.h> main() { char answer; printf("Would you like to know my name?n"); printf("Type Y for YES and N for NO: "); answer = getchar(); /* .... Reading a character...*/ if(answer == 'Y' || answer == 'y') printf("nnMy name is BUSY BEEn"); else printf("nnYou are good for nothingn"); }
- 5. The program of requests the user to enter a character and displays a message on the screen telling the user whether the character is an alphabet or digit, or any other special character This program receives a character from the keyboard and tests whether it is a letter or digit and prints out a message accordingly. These tests are done with the help of the following functions: isalpha(character) isdigit(character) For example, isalpha assumes a value non-zero (TRUE) if the argument character contains an alphabet; otherwise it assumes 0 (FALSE). Similar is the case with the function isdigit
- 6. #include <stdio.h> #include <ctype.h> main() { char character; printf("Press any keyn"); character = getchar(); if (isalpha(character) > 0) printf("The character is a letter."); else if (isdigit (character) > 0) printf("The character is a digit."); else printf("The character is not alphanumeric."); }
- 7. The program uses three new functions: islower, toupper, and tolower. The function islower is #include <stdio.h> #include <ctype.h> main() { char alphabet; printf("Enter an alphabet"); putchar('n'); /* move to next line */ alphabet = getchar(); if (islower(alphabet)) putchar(toupper(alphabet)); else putchar(tolower(alphabet)); }
- 8. #include <stdio.h> #include <ctype.h> main() { char alphabet; printf("Enter an alphabet"); putchar('n'); /* move to next line */ alphabet = getchar(); if (isupper(alphabet)) putchar(tolower(alphabet)); else putchar(toupper(alphabet)); }