Problem Solving & C Programming Basics

• Problem-solving is the process of finding a solution to a difficult or complex issue

Problem-Solving Techniques

• Algorithmic approach: Develop a step-by-step procedure to solve the problem.
• Break down the problem: Divide a complex problem into smaller, manageable parts.
• Start with what you know: Use existing knowledge to find a solution.
• Trial and error: Experiment with different solutions until you find one that works.
• Research: Gather information relevant to the problem

Programming in C

• C is a procedural, compiled programming language.
• It is known for its efficiency and control over system hardware.
• Compilation: C code is translated into machine code that can be executed by the computer.
• Syntax: C has a specific syntax that must be followed for code to compile correctly

Basic Structure of a C Program

• Header files inclusion: Including standard libraries for functions like input/output.
• Main function: The entry point of the program (int main()).
• Declarations: Declaring variables to store data.
• Statements: Instructions to perform actions.
• Return statement: Returns a value from the main function (return 0;).

Variables in C

• Definition: Named storage locations that hold values.
• Declaration: Specifying the variable's name and data type.
• Initialization: Assigning an initial value to a variable.
• Data types: int (integer), float (floating-point), char (character), double (double-precision floating-point).

Operators in C

• Arithmetic operators: +, -, *, /, % (modulus).
• Assignment operators: =, +=, -=, *=, /=, %=.
• Comparison operators: ==, !=, >, <, >=, <=.
• Logical operators: && (AND), || (OR), ! (NOT).

Input and Output in C

• printf(): Used to print output to the console.
• scanf(): Used to read input from the console.
• Format specifiers: Used to specify the data type being printed or read (%d for int, %f for float, %c for char).

Control Structures in C

• Conditional statements: if, else if, else.
• Switch statement: A multi-way decision statement.
• Loops: for, while, do-while

Loops

• Loops are used to repeat a block of code multiple times.
• Types of loops: for, while, and do-while.
• Loop control statements: break and continue.

For Loop

• Structure: for (initialization; condition; increment/decrement) { /* code */ }
• Initialization: Executed once before the loop starts.
• Condition: Checked before each iteration; if true, the loop continues.
• Increment/Decrement: Executed after each iteration.
• Example: for (int i = 0; i < 10; i++) { printf("%d ", i); } prints numbers 0 to 9.

While Loop

• Structure: while (condition) { /* code */ }
• Condition: Checked before each iteration; if true, the loop continues.
• The loop continues as long as the condition is true.
• Example:

int i = 0;
while (i < 10) {
    printf("%d ", i);
    i++;
}

• Prints numbers 0 to 9.

Do-While Loop

• Structure: do { /* code */ } while (condition);
• The code block is executed at least once.
• Condition: Checked after each iteration; if true, the loop continues.
• Example:

int i = 0;
do {
    printf("%d ", i);
    i++;
} while (i < 10);

• Prints numbers 0 to 9.

Break Statement

• Purpose: Terminates the loop prematurely
• When break is encountered inside a loop, the loop exits immediately
• Commonly used to exit loops based on certain conditions
• Example:

for (int i = 0; i < 10; i++) {
    if (i == 5) {
        break; // Exit loop when i is 5
    }
    printf("%d ", i);
}

• Output: 0 1 2 3 4

Continue Statement

• Purpose: Skips the rest of the current iteration and proceeds to the next iteration
• When continue is encountered, statements after continue in the loop body are skipped for the current iteration
• Commonly used to avoid executing certain parts of the loop body based on conditions
• Example:

for (int i = 0; i < 10; i++) {
    if (i == 5) {
        continue; // Skip printing when i is 5
    }
    printf("%d ", i);
}

• Output: 0 1 2 3 4 6 7 8 9

Nested Loops

• Definition: Placing one loop inside another
• The inner loop completes all its iterations for each iteration of the outer loop
• Commonly used for operations on multi-dimensional arrays or matrices
• Example:

for (int i = 0; i < 3; i++) {
    for (int j = 0; j < 3; j++) {
        printf("(%d, %d) ", i, j);
    }
    printf("\n");
}

• Output:

(0, 0) (0, 1) (0, 2)
(1, 0) (1, 1) (1, 2)
(2, 0) (2, 1) (2, 2)

Common Loop Mistakes

• Infinite loops: Occur when the loop condition never becomes false.
• Off-by-one errors: Occur when the loop iterates one time too many or too few.
• Incorrect loop condition: Occurs when the loop condition is not set up correctly.
• Forgetting to update the loop counter: Results in unexpected behavior or infinite loops.