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PSeInt Mientras (while loop): how it works, with an example

Repeats a group of instructions while the condition stays true. It checks the condition before every round, so if it's already false at the start, nothing repeats.

Group:
Structures
Template
Mientras
Open it in Codoritmo

Opens the editor with this example loaded. Run it step by step and watch the flowchart.

Worked example

A complete algorithm, ready to copy and run.

mientras-while-loop.psc · 7 lines
Algoritmo Example    contador <- 1    Mientras contador <= 3 Hacer        Escribir contador        contador <- contador + 1    FinMientrasFinAlgoritmo

Output

Shows 1, 2 and 3, one per line.

This is what the console shows when the example runs.

123

Common mistake

Something inside must change the condition, or the loop never ends.

In a flowchart

This is how it appears in a flowchart, with the same shapes Codoritmo draws.

contador <= 3Sí…No
In the flowchart. Flowchart: a decision diamond with the condition "contador <= 3"; on Sí (yes) it runs the body and loops back to the condition, on No it leaves the loop.
Draw the flowchart of your own algorithm →

Template

The general form. Replace what's inside < > with your own data.

Mientras · 3 lines
Mientras <condicion> Hacer  <acciones>FinMientras

Examples that use it

Programs from the example library where it appears, from the simplest to the most complete.

  • Sum Until Zero

    Adds up the numbers you type until you enter a 0.

    Beginner

  • Guess the Number

    Guess a secret number from 1 to 100 in seven tries.

    Intermediate

  • Linear Search

    Finds a name in a list, ignoring upper and lower case.

    Intermediate

  • Bubble Sort

    Sorts random numbers by swapping neighbors, and stops as soon as they're in order.

    Intermediate

  • Insertion Sort

    Inserts each number among the sorted ones, like arranging cards in your hand.

    Intermediate

  • Binary Search

    Finds a value in a sorted array by halving the range every step.

    Intermediate
See every Mientras example →

More structures

Codoritmo is an independent, open-source project inspired by PSeInt and compatible with its syntax. It is not affiliated with the PSeInt project. Official PSeInt website.