UNIT 3 : Flow Control Structures
Flow control structures in C programming empower you to manage the sequence of actions in your program based on conditions or repetition. The three primary control structures in C are:
1. Conditional (if-else) Statements:
These are employed to execute a block of code only when a specific condition is satisfied.
Example:
```c
int x = 10;
if (x > 5) {
printf("x is greater than 5");
}
```
2. Loops:
Used to iteratively execute a block of code until a particular condition is met.
Example:
```c
for (int i = 0; i < 10; i++) {
printf("%d\n", i);
}
```
3. Switch Statements:
These allow you to choose one block of code from multiple options based on the value of an expression.
Example:
```c
char grade = 'B';
switch (grade) {
case 'A':
printf("Excellent!");
break;
case 'B':
printf("Good!");
break;
case 'C':
printf("Average");
break;
default:
printf("Invalid grade");
}
```
Decision Making Structures:
Decision-making structures in C are employed to make choices in a program based on certain conditions. There are two main decision-making structures:
1. if Statement:
Used to execute a block of code only if a specified condition is true.
Example:
```c
int x = 10;
if (x > 5) {
printf("x is greater than 5");
}
```
2. if-else Statement:
Allows execution of one block of code if a condition is met and another if the condition is not met.
Example:
```c
int x = 10;
if (x > 5) {
printf("x is greater than 5");
} else {
printf("x is not greater than 5");
}
```
Loop Control Structures:
Loop control structures in C are utilized to repetitively execute code until a certain condition is satisfied. The three primary loop control structures are:
1. for Loop:
Used to execute a block of code a specific number of times.
Example:
```c
for (int i = 0; i < 10; i++) {
printf("%d\n", i);
}
```
2. while Loop:
Executes a block of code as long as a specified condition is true.
Example:
```c
int i = 0;
while (i < 10) {
printf("%d\n", i);
i++;
}
```
3. do-while Loop:
Similar to the while loop but ensures that the code inside the loop is executed at least once.
Example:
```c
int i = 0;
do {
printf("%d\n", i);
i++;
} while (i < 10);
```
Nested Control Structures:
Nested if-else and nested for loop structures enable testing multiple conditions and running inner loops for each iteration of an outer loop.
Example:
```c
int x = 10, y = 20;
if (x > 5) {
if (y > 15) {
printf("x is greater than 5 and y is greater than 15");
} else {
printf("x is greater than 5 and y is not greater than 15");
}
} else {
printf("x is not greater than 5");
}
```
Break, Continue, Goto, Exit:
These statements provide control over the flow of a program.
- break: Exits a loop prematurely.
Example:
```c
for (int i = 0; i < 10; i++) {
if (i == 5) {
break;
}
printf("%d\n", i);
}
```
- continue:Skips the current iteration of a loop and proceeds to the next.
Example:
```c
for (int i = 0; i < 10; i++) {
if (i % 2 == 0) {
continue;
}
printf("%d\n", i);
}
```
- goto: Jumps to a labeled statement in the program.
Example:
```c
for (int i = 0; i < 10; i++) {
if (i == 5) {
goto end;
}
printf("%d\n", i);
}
end:
printf("Reached end of program.\n");
```
- exit: Immediately exits a program with a status value.
Example:
```c
for (int i = 0; i < 10; i++) {
if (i == 5) {
exit(0);
}
printf("%d\n", i);
}
```
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