All loops have the same function, which is to repeat an instruction a certain or undetermined number of times.
The structure of the FOR loop is as follows:
for(inicialização; condição; incremento) comandos;
For example:
#include
voi main()
{
int x;
for(x = 0; x <= 100; x++) printf("%d", x); }
The program above displays numbers from 0 to 100 on the screen. The FOR loop is usually also used to make infinite loops since its fields are not mandatory, but this is just a custom, which does not prevent you from using the WHILE loop instead of FOR.
Example of an infinite loop with FOR:
#include
void main()
{
int x;
for(x = 0; ; x++)
printf("%d", x);
}
Structure of the While loop:
while(condição) comando;
Example:
include
void main()
{
int x;
while(x != 0)
{
printf("Insira um valor para X: ");
scanf("%d", x);
}
}
The WHILE loop is repeated until the user enters the value zero.
Structure of the Do-While loop:
do{
comando1;
comando2;
}
while(condição);
The Do-While loop, unlike the FOR and WHILE loops, tests the condition at the end of execution, i.e. the commands inside the ‘Do’ keys:
do{
command1;
command2;
}
are executed, then the condition inside the WHILE is tested, if true the commands inside the ‘Do’ braces are executed again, if false the program exits the loop.
