C Video Tutorial 7
Welcome to part 7 of my C Video Tutorial! In this tutorial, I’m going to cover a bunch of topics that you have requested and that I have skipped.
I cover the following: strchr(), strrchr(), tolower(), toupper(), ctype.h Functions, _Bool, bool, Numerous Ways to Except Input, getchar(), putchar(), Buffering, gets(), puts(), fgets(), fputs(), How to Eliminate Newline, How to Make a String Lowercase, strcmp() and more.
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Code From the Video
CTutorial7.c
#include <stdio.h>
// Needed if you want to use bool
#include <stdbool.h>
#include <string.h>
#include <ctype.h>
// Used to remove a newline
void noMoreNewline(char* theString){
char * isANewline;
// strchr() returns a pointer to the first location
// of the character provided
// strrchr() returns the last occurance
isANewline = strrchr(theString, '\n');
if(isANewline){
*isANewline = '\0';
}
}
// Used to make all letters lowercase
void makeLowercase(char* theString){
int i = 0;
while(theString[i]){
// tolower() converts char to lowercase
// toupper() does the opposite
theString[i] = tolower(theString[i]);
i++;
}
}
void getCharInfo(){
char theChar;
while ((theChar = getchar()) != '\n'){
printf("Letter or Number %d\n\n", isalnum(theChar));
printf("Alphabetic Char %d\n\n", isalpha(theChar));
printf("Standard Blank %d\n\n", isblank(theChar));
printf("Ctrl Char %d\n\n", iscntrl(theChar));
printf("Number Char %d\n\n", isdigit(theChar));
printf("Anything But Space %d\n\n", isgraph(theChar));
printf("Lowercase %d\n\n", islower(theChar));
printf("Uppercase %d\n\n", isupper(theChar));
printf("Anything not a Letter, Number or Space %d\n\n", ispunct(theChar));
printf("Any Space %d\n\n", isspace(theChar));
}
}
void main(){
/* _Bool and bool data type ------
// _Bool is the C boolean type. It holds either a 1 (true)
// or a 0 (false)
_Bool isANumber;
// If #include <stdbool.h> is above you can use bool here
// It defines true as a constant for 1 and false for 0
int number;
int sumOfNumbers;
printf("Enter a number: ");
// Checks if data matching the format specifier was entered
// (0-9) with a + or minus. If true a 1 is returned
isANumber = (scanf("%d", &number) == 1);
// When they enter data that doesn't match the format specifier
// %d the loop ends
while(isANumber){
sumOfNumbers = sumOfNumbers + number;
printf("Enter another number: ");
isANumber = (scanf("%d", &number) == 1);
}
printf("The Sum is %d\n\n", sumOfNumbers);
*/
/* Demonstrate getchar, putchar and buffering
char theChar;
// With this compiler getchar() will wait until the enter
// button is pressed and then push everything to the screen.
// The data is stored in a buffer as it is entered. The buffer
// is a temporary storage area in memory. The size of the buffer
// depends on the system. In essence a buffer is just a pointer
// without a specified size. This is an example of line
// buffering because the buffer ends when a newline is entered.
while ((theChar = getchar()) != '~'){
putchar(theChar);
}
*/
/* Demonstrate gets(), puts(), fgets(), fputs()
char name[50];
printf("What is your name? ");
// The gets() function recieves a string from the keyboard
// until a \n is reached. It then replaces the \n with \0
// Be careful with gets because it doesn't check if the input
// fits in the 50 character space. That is why I have been
// using fgets()
gets(name);
// puts() receives a string and prints it out followed by
// a new line
puts("Hi");
puts(name);
printf("What is your name? ");
// fgets() reads till the array limit is reached or till \n
// It appends a \n to the end of the array
fgets(name, 50, stdin);
// fputs() prints strings without a \n
fputs("Hi ", stdout);
fputs(name, stdout);
*/
/*
// Demonstrate a confusing way to print strings
// Create a string array (pointer to first element in array)
char * randomString = "Just some random stuff";
// while continues until it reaches a null character, which
// with *randomString is equal to 0
while(*randomString){
// Prints a character in the array and then increments
// to the next
putchar(*randomString++);
}
puts("\n");
*/
// The above is the same as
/*
char * randomString = "Just some random stuff";
int i = 0;
while(randomString[i] != '\0'){
putchar(randomString[i++]);
}
*/
/* Solving more random problems
char doYouWantToQuit[10];
printf("Enter quit to quit: ");
fgets(doYouWantToQuit, 10, stdin);
// fgets() adds a newline at the end. To get rid of it
// Deletes the newline from the string
noMoreNewline(doYouWantToQuit);
// Make letters lowercase
makeLowercase(doYouWantToQuit);
// strcmp() returns 0 when the strings are equal
while(strcmp(doYouWantToQuit, "quit")){
printf("Enter quit to quit: ");
fgets(doYouWantToQuit, 10, stdin);
noMoreNewline(doYouWantToQuit);
makeLowercase(doYouWantToQuit);
}
printf("Thank you for typing %s\n\n",doYouWantToQuit);
*/
// Testing ctype.h Functions
getCharInfo();
}
You are amazing. It’s cool, that you make these code snippets with comments 🙂 It’s really helping me. Thank you very much
Thank you 🙂 I did my best to transcribe what I say in the videos to help those in which english is a second language. I’m glad they are helping