loop:
it is a process of repeating or iterating a block of code until a condition becomes false.
There are different types of loops:
entry controlled loop:
loops where conditions are checked before the execution of the specified block of code.
entry controlled loops are:
1. for loop
2. while loop
exit controlled loop :
loops where conditions are checked after the execution of the specified block of code.
exit controlled loops are:
1. do-while loop
for loop
for loop is used to repeat a block of code with a limit.
for (starting;condition;increment/decrement)
{
//code to repeat
}
note:
example: print from 5 to 0
starting:
int i=5;
condition:
i>=0
decrement: subtract a value by one
i--;
code:
for(int i=5;i>=0;i--)
{
cout<<i<<endl;
}
example: print from 0 to 4
starting:
int j=0;
condition:
j<5
increment:add a value by one
j++;
code:
for(int j=0;j<5;j++)
{
cout<<j<<endl;
}
while loop
while loop is used to repeat or iterate a block of code until a condition becomes false.
syntax:
while(condition)
{
//code to repeat
}
int i=7;
while(i<9)
{
cout<<i<<endl;
i++;
}
int j=9;
while(j>6)
{
cout<<j<<endl;
j--;
}
exit controlled loop
========================
1. it is a loop that is used when there is a need to execute a block of code at least one time.
2. do-while loop firstly, executes the block of code and then checks the given condition.
do-while loop
do
{
//code to repeat
}while(condition);
example:
print from 8 to 49
int i=8;
do
{
cout<<i<<endl;
i++;
}while(i<50);
print from 49 to 8
int j=49;
do
{
cout<<j<<endl;
j--;
}while(j<8);
array
1. it is used to hold or store multiple values.
2. it can hold any single type of value.
3. can hold a fixed amount of values.
4. arrays are indexed.
for example:
the first element is in the 0 position.
the second element is in the 1 position and so on.
syntax:
data_type var_name[number_of_elements];
example:
#include<iostream>
using namespace std;
int main()
{
int nums[9];
char data[6];
float heights[8];
string names[89];
return 0;
}
how to initialize an array
or
how to store values in an array
manual
1. one-dimensional array
example:
float heights[7]={5.4,3.6,7.8,2.4,6.5,7.8,9.7};
how to single element of an array
#include<iostream>
using namespace std;
int main()
{
int ages[9]={4,6,3,7,9,4,7,9,3}
cout<<ages[0]; //how to print first element
cout<<ages[1]; //how to print second element
cout<<ages[8]; //how to print last element
return 0;
}
how to print all elements of an array?
#include<iostream>
using namespace std;
int main()
{
int ages[9]={4,6,3,7,9,4,7,9,3}
for(int index=0;index<9;index++)//
{
cout<<ages[index]<<endl;
}
return 0;
}
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