C Tutorial Lecture#4

 

Control Flow Statements in C

If-Else Statements

The if statement is used to execute a block of code if a specified condition is true. The else statement can be used to execute a block of code if the condition is false.

int a = 10;
if (a > 5) {
    printf("a is greater than 5\n");
} else {
    printf("a is not greater than 5\n");
}
  

Switch Statement

The switch statement is used to execute one block of code among many, based on the value of a variable.

int day = 3;
switch (day) {
    case 1:
        printf("Monday\n");
        break;
    case 2:
        printf("Tuesday\n");
        break;
    case 3:
        printf("Wednesday\n");
        break;
    default:
        printf("Other day\n");
}
  

Loops

Loops are used to execute a block of code repeatedly. C provides three types of loops:

For Loop

The for loop is used when the number of iterations is known.

for (int i = 0; i < 5; i++) {
    printf("%d\n", i);
}
  

While Loop

The while loop is used when the number of iterations is not known, and it continues until a condition is false.

int i = 0;
while (i < 5) {
    printf("%d\n", i);
    i++;
}
  

Do-While Loop

The do-while loop is similar to the while loop but guarantees that the block of code is executed at least once.

int i = 0;
do {
    printf("%d\n", i);
    i++;
} while (i < 5);
  

Break and Continue Statements

The break statement is used to exit from a loop or switch statement, while the continue statement is used to skip the current iteration and proceed to the next iteration of the loop.

Example of break:

for (int i = 0; i < 10; i++) {
    if (i == 5) {
        break;
    }
    printf("%d\n", i);
}
  

Example of continue:

for (int i = 0; i < 10; i++) {
    if (i == 5) {
        continue;
    }
    printf("%d\n", i);
}
  

Nested Loops and Conditional Statements

Loops and conditional statements can be nested within each other to perform complex tasks.

for (int i = 0; i < 3; i++) {
    for (int j = 0; j < 2; j++) {
        if (i == j) {
            printf("i equals j when i=%d and j=%d\n", i, j);
        } else {
            printf("i does not equal j when i=%d and j=%d\n", i, j);
        }
    }
}
  

Summary

Understanding control flow statements is essential for programming in C. This post covered if-else statements, switch statements, loops, break and continue statements, and nested loops and conditional statements.

For more detailed information, you can refer to the following resources:

• Learn-C.org
• GeeksforGeeks - C Programming

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