cout C

Syntax of cout in C

• printf() - This function is used to display output on the screen. It is defined in the stdio.h library. The prototype is: int printf(const char *format, ...); where 'format' contains conversion specifiers and escape sequences for formatting the output, and the ellipsis (...) denotes a variable number of additional arguments.
• fscanf() - This function is used to read formatted data from a file. It is defined in the stdio.h library. The prototype is: int fscanf(FILE *stream, const char *format, ...);
• getchar() - This function is used to read a single character from the stdin (keyboard). It is defined in the stdio.h library. The prototype is: int getchar(void);
• putchar() - This function is used to write a single character to the stdout (screen). It is defined in the stdio.h library. The prototype is: int putchar(int character);

Common cout operations in C

Working with cout in C for Strings

Once again, keep in mind that cout is primarily associated with C++ programming. For outputting strings in C programming, you can utilise the printf() function. Like other data types, printf() supports outputting strings by using the %s format specifier. To output a string using printf():

• Declare a character array to store the string.
• Initialize the string using string literals or manual assignment of characters.
• Pass the character array as an argument in the printf() function, along with %s format specifier.

#include

int main()
{
   char greetings[] = "Hello, World!";
   printf("%s", greetings);
   return 0;
}

Formatting Strings with cout in C

• Width specifiers: To align or pad strings in the output, you can use width specifiers in the form of a number following the % symbol, like %10s or %5s.
• Precision specifiers: To limit the number of characters displayed, you can use precision specifiers in the form of a number preceded by a period (.), like %.3s.
• Escape sequences: To include special characters in the output, use escape sequences, like \t for a tab, and \n for a newline.

#include

int main()
{
   char songTitle[] = "Imagine";
   char artist[] = "John Lennon";
   printf("Song: %-30s Artist: %s\n", songTitle, artist);
   return 0;
}

Handling User Input with cin and cout in C Programming

• Declare appropriate data type variables or character arrays to store inputs.
• Utilise scanf() with proper format specifiers to match the data type of the input being read.
• Use the address-of operator (&) for non-string inputs, like int, float, and char variables.
• Process the input data as desired.

#include

int main()
{
   char name[50];
   int age;
   
   printf("Enter your name: ");
   fgets(name, sizeof(name), stdin);

   printf("Enter your age: ");
   scanf("%d", &age);
   
   printf("Hello, %sYou are %d years old.", name, age);
   return 0;
}

Delving into C cout examples

#include

int main()
{
   // Outputting an integer
   int number = 5;
   printf("Integer: %d\n", number);

   // Outputting a floating-point number
   float fnumber = 3.14;
   printf("Float: %f\n", fnumber);

   // Outputting a character
   char letter = 'A';
   printf("Character: %c\n", letter);

   // Outputting a string
   char text[] = "Hello, C!";
   printf("String: %s\n", text);

   return 0;
}

Advanced C output examples

#include

int main()
{
   // Outputting multiple data types
   int age = 25;
   float salary = 2500.00;
   char name[] = "John Doe";
   printf("Name: %s\nAge: %d\nSalary: %.2f\n", name, age, salary);

   // Using escape sequences for formatting
   printf("Heading\t:\tResult\n");
   printf("Maths\t:\t90%%\n");
   printf("Physics\t:\t85%%\n");

   // Combination of input and formatted output
   int itemNo;
   float price;

   printf("Enter item number: ");
   scanf("%d", &itemNo);

   printf("Enter price: ");
   scanf("%f", &price);

   printf("Item: %04d\n", itemNo);
   printf("Price: £%.2f\n", price);

   return 0;
}

C output explained with real-world scenarios

#include

int main()
{
   printf("Number\tSquare\tCube\n");
   for (int i = 1; i <= 10; i++)
   {
      printf("%d\t%d\t%d\n", i, i * i, i * i * i);
   }
   return 0;
}

#include

int main()
{
   int n;
   float prices[5] = {1.99, 3.50, 2.35, 4.20, 6.75};
   
   printf("Enter the quantity of each item:\n");
   int quantities[5];
   
   for (int i = 0; i < 5; i++)
   {
      printf("Item %d: ", i + 1);
      scanf("%d", &quantities[i]);
   }
   
   printf("\nInvoice:\n");
   printf("Item\tQty\tPrice\tTotal\n");
   
   float subTotal = 0;
   for (int i = 0; i < 5; i++)
   {
      float itemTotal = prices[i] * quantities[i];
      printf("%d\t%d\t£%.2f\t£%.2f\n", i + 1, quantities[i], prices[i], itemTotal);
      subTotal += itemTotal;
   }

   float tax = subTotal * 0.07;
   float grandTotal = subTotal + tax;

   printf("\nSubtotal: £%.2f\n", subTotal);
   printf("Tax (7%%): £%.2f\n", tax);
   printf("Total: £%.2f\n", grandTotal);
   
   return 0;
}

Using C cout effectively in your code

• Choose the appropriate format specifier for the data type you want to output. For example, use %d for integers, %f for floats, and %s for strings.
• Ensure that the variable you pass as an argument to scanf() function is referred with the address-of operator (&) if it is a non-string data type.
• For string manipulation, consider using additional string functions from the string.h library like strncpy(), strcat(), or strcmp().
• To avoid security vulnerabilities and unexpected behaviour, use secure input/output functions like fgets() instead of gets() and snprintf() instead of sprintf().
• Utilise escape sequences to format output properly by introducing new lines, tabs, or other special characters within the text.
• Make use of width and precision specifiers to align and format outputs nicely and consistently, especially when displaying tables or multiple fields within your output.

Best practices for C cout and cin programming

1. Choose the right function: Determine whether to use printf() or one of the alternatives for outputting data based on your requirements. Similarly, for input, choose between scanf() and other input functions like fgets() or fscanf().
2. Consistent formatting: Strive for consistency when setting up the formatting of your output, particularly when using several printf() statements alongside each other. Consistency helps make your output easier to read.
3. Secure input functions: Avoid using unsafe functions like gets(). Opt for fgets() instead to prevent potential security vulnerabilities like buffer overflow attacks.
4. Check for errors in input and output functions: Validate the return values of input and output functions to ensure error-free operation and to handle exceptions accordingly.
5. Use proper casting: When using variables of different data types, make sure to cast them explicitly to avoid unintentional conversions and potential errors in your code.
6. Automate repetitive tasks: If you find yourself repeating a specific operation, consider creating a function to handle that operation and streamline your code.