C Language Tutorial313

IntroductionC is a general-purpose, procedural programming language that was developed in the 1970s by Dennis Ritchie at AT&T Bell Labs. It is a structured programming language that supports procedural and object-oriented programming. C is one of the most popular programming languages in the world and is used in a wide variety of applications, including operating systems, databases, and compilers.

Basic SyntaxA C program consists of a set of functions, where the main function is the entry point of the program. The main function is called when the program is executed. All C programs must include the following header file:```c
#include
```

This header file contains the declarations for the input/output functions, such as printf() and scanf().

Data TypesC supports a variety of data types, including integer, floating-point, and character. The following table shows the most common data types in C:| Data Type | Description |
|---|---|
| int | Integer |
| float | Floating-point number |
| double | Double-precision floating-point number |
| char | Character |

VariablesVariables are used to store data in C. Variables must be declared before they can be used. The general syntax for declaring a variable is:```c
data_type variable_name;
```

For example, the following declaration creates an integer variable named age:```c
int age;
```

OperatorsC supports a variety of operators, including arithmetic, logical, and bitwise operators. The following table shows the most common operators in C:| Operator | Description |
|---|---|
| + | Addition |
| - | Subtraction |
| * | Multiplication |
| / | Division |
| % | Modulus |
| == | Equality |
| != | Inequality |
| < | Less than |
| > | Greater than |
| = | Greater than or equal to |

Control FlowC provides several control flow statements, including if-else statements, switch statements, and while and for loops. The following example shows an if-else statement:```c
if (age >= 18) {
printf("You are an adult.");
} else {
printf("You are a child.");
}
```

The following example shows a switch statement:```c
switch (age) {
case 18:
printf("You are an adult.");
break;
case 16:
printf("You are a teenager.");
break;
default:
printf("You are a child.");
}
```

The following example shows a while loop:```c
while (age >= 18) {
printf("You are an adult.");
age--;
}
```

The following example shows a for loop:```c
for (int i = 0; i < age; i++) {
printf("Your age is %d.", i);
}
```

FunctionsFunctions are used to group code together into reusable blocks. Functions can be called from other parts of the program. The general syntax for declaring a function is:```c
return_type function_name(parameter_list) {
// Function body
}
```

For example, the following function calculates the factorial of a number:```c
int factorial(int n) {
if (n == 0) {
return 1;
} else {
return n * factorial(n - 1);
}
}
```

ArraysArrays are used to store a collection of data items of the same type. Arrays are declared using the following syntax:```c
data_type array_name[size];
```

For example, the following declaration creates an array of 10 integers:```c
int numbers[10];
```

StructuresStructures are used to store a collection of data items of different types. Structures are declared using the following syntax:```c
struct struct_name {
data_type member_name;
data_type member_name;
...
};
```

For example, the following declaration creates a structure to store a person's name, age, and address:```c
struct person {
char name[50];
int age;
char address[100];
};
```

PointersPointers are used to store the address of a variable. Pointers are declared using the following syntax:```c
data_type *pointer_name;
```

For example, the following declaration creates a pointer to an integer:```c
int *ptr;
```

File HandlingC provides several functions for reading from and writing to files. The following example shows how to open a file for reading:```c
FILE *fp = fopen("", "r");
```

The following example shows how to read a line from a file:```c
char line[100];
fgets(line, 100, fp);
```

The following example shows how to write a line to a file:```c
fprintf(fp, "This is a line of text.");
```

ConclusionC is a powerful and versatile programming language that can be used for a wide variety of applications. This tutorial has covered the basics of the C programming language, including data types, variables, operators, control flow, functions, arrays, structures, pointers, and file handling. For more in-depth information, please refer to the C programming language documentation.

2024-11-19

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