10
meiLoop in C++: A Detailed Discussion with Examples
Loops in C ++: An Overview
loop
? Looping is one of the key concepts behind programming, and learning how to use loops
in C++ can open up a new world of code. Gain the foundational skills from this C++ tutorial and move to the advanced C++ training that includes in-depth coverage of loops
and other essential programming concepts.What are loops in C++?
Loops
are a block of code that executes itself until the specified condition becomes false. In this section, we will look in detail at the types of loops
used in C++ programming.What is the need for Looping Statements in C++?
We can give some uses ofloops
in C++:
Loops
allow the user to execute the same set of statements repeatedly without writing the same code multiple times.- It saves time and effort and increases the efficiency.
- It reduces the chance of getting errors during compilation.
Loop
makes the code readable and easier to understand, especially when dealing with complex logic or large data sets.- It promotes code reusability.
Loops
help traverse data structures like arrays or linked lists.
Read More - C++ Interview Questions Interview Questions for Freshers
Types of Loops in C++
loops
used in C++ programming:for
loop
while
loopdo while
loop
In this article, we will look at the C++ for
loop in detail. The other two loops will be covered subsequently after this.
1.) for loop in C++
Afor
loop is a control structure that enables a set of instructions to get executed for a specified number of iterations. It is an entry-controlled loop.
Syntax
for(initialization; testcondition; updateExpression)
{
//code to be executed
}
- Here, the
initialization
statement is executed first and only once. - The
testcondition
is checked, iffalse
the loop terminates - If the
testcondition
istrue
, the body of the loop executes - The
update expression
gets updated - Again the
testcondition
is evaluated - The process repeats until the
testcondition
becomesfalse
.
Example in C++ Compiler
// Program to print numbers from 1 to 10
#include <iostream>
using namespace std;
int main() {
for (int i = 1; i <= 10; i++) {
cout << i << endl;
}
return 0;
}
for
loop in C++.- We know it will take 10 iterations to print 10 numbers so, we have used the
for
loop. i
is initialized to 0.- The condition
i<10
will be checked. It is true, thereforei+1
i.e. 1 gets printed. - Then
i
increments to 1 again the condition,i<10
is evaluated. - The process will repeat until
i
become 10.
Output
1
2
3
4
5
6
7
8
9
10
2.) Nested for loop in C++
for
loop.
Example
#include <iostream>
using namespace std;
int main() {
for (int i = 1; i <= 5; i++) {
for (int j = 1; j <= i; j++) {
cout << j << " ";
}
cout << endl;
}
return 0;
}
- This C++ code generates a pattern of numbers using nested loops.
- The inner loop
j
iterates from 1 to the current value ofi
, printing numbers and spaces - The outer loop
i
iterates from 1 to 5, regulating the number of rows. - As a result, there is a pattern of numerals rising in each row, with a new line between each row.
Output
1
1 2
1 2 3
1 2 3 4
1 2 3 4 5
3.) Infinite for loop in C++
An infinitefor
loop gets created if the for
loop condition remains true
, or if the programmer forgets to apply the test condition/terminating statement
within the for
loop statement.
Syntax
for(; ;)
{
// body of the for loop.
}
In the above syntax, there is no condition hence, this loop will execute infinite times.
Example
#include <iostream>
int main() {
for (;;) {
std::cout << "Hello World" << std::endl;
}
return 0;
}
for
loop infinite times, so "Hello World" will be displayed infinitely.
Output
Hello World Hello World Hello World Hello World Hello World ...
4.) for-each loop/ range-based for loop
This is a new kind of loop introduced in theC++11
version. It is used exclusively to traverse through elements in an array
and vector
.
Syntax
for (variableName : arrayName/vectorName) {
// code block to be executed
}
Here, for every value in the array
or vector
, the for
loop is executed and the value is assigned to the variable.
Example in C++ Editor
#include <iostream>
using namespace std;
int main() {
int num[7] = {10, 20, 30, 40, 50, 60, 70};
for (int i : num) {
cout << i << "\n";
}
return 0;
}
Output
10
20
30
40
50
60
70
Summary
for
loop in C++ programming. We also saw infinite
and nested for
loop. Finally, we also discussed the new concept of for-each
loop. If you want to learn more about programming in C++, you can enrol in our C++ certification training or check out our website for tutorials on various topics.Take our free skill tests to evaluate your skill!
In less than 5 minutes, with our skill test, you can identify your knowledge gaps and strengths.