Goalkeeper (association football)

Goalkeeper, often shortened to keeper or goalie, is one of the major positions of association football. It is the most specialised position in the sport. The goalkeeper's primary role is to prevent the opposing team from successfully moving the ball over the defended goal-line (between the posts and under the crossbar). This is accomplished by the goalkeeper moving into the path of the ball and either catching it or directing it away from the vicinity of the goal line and also becoming the so-called brick wall. Within the penalty area goalkeepers are able to use their hands, making them (outside of throw-ins) the only players on the field able to handle the ball. Goalkeepers usually perform goal kicks, and also give commands to their defence during corner kicks, direct and indirect free kicks, and marking. Goalkeepers play an important role in directing on field strategy as they have an unrestricted view of the entire pitch, giving them a unique perspective on play development. If an attacker on the opposing team obstructs the keeper from catching or saving the ball, for example, in a corner, it will normally be a free kick.

Association football

Association football, more commonly known as football or soccer, is a sport played between two teams of eleven players with a spherical ball. It is played by 250 million players in over 200 nations, making it the world's most popular sport. The game is played on a rectangular field with a goal at each end. The object of the game is to score by getting the ball into the opposing goal.

The goalkeepers are the only players allowed to touch the ball with their hands or arms while it is in play and only in their penalty area. Outfield players mostly use their feet to strike or pass the ball, but may also use their head or torso to do so instead. The team that scores the most goals by the end of the match wins. If the score is level at the end of the game, either a draw is declared or the game goes into extra time and/or a penalty shootout depending on the format of the competition. The Laws of the Game were originally codified in England by The Football Association in 1863. Association football is governed internationally by the International Federation of Association Football (FIFA; French: Fédération Internationale de Football Association), which organises World Cups for both men and women every four years.

Ball (association football)

A football, soccer ball, or association football ball is the ball used in the sport of association football. The name of the ball varies according to whether the sport is called "football", "soccer", or "association football". The ball's spherical shape, as well as its size, weight, and material composition, are specified by Law 2 of the Laws of the Game maintained by the International Football Association Board. Additional, more stringent, standards are specified by FIFA and subordinate governing bodies for the balls used in the competitions they sanction.

Early footballs began as animal bladders or stomachs that would easily fall apart if kicked too much. Improvements became possible in the 19th century with the introduction of rubber and discoveries of Vulcanization by Charles Goodyear. The modern 32-panel ball design was developed in 1962 by Eigil Nielsen, and technological research continues today to develop footballs with improved performance.

History

In 1863, the first specifications for footballs were laid down by the Football Association. Previous to this, footballs were made out of inflated leather, with later leather coverings to help footballs maintain their shapes. In 1872 the specifications were revised, and these rules have been left essentially unchanged as defined by the International Football Association Board. Differences in footballs created since this rule came into effect have been to do with the material used in their creation.

Football

Football is a family of team sports that involve, to varying degrees, kicking a ball to score a goal. Unqualified, the word football is understood to refer to whichever form of football is the most popular in the regional context in which the word appears. Sports commonly called 'football' in certain places include: association football (known as soccer in some countries); gridiron football (specifically American football or Canadian football); Australian rules football; rugby football (either rugby league or rugby union); and Gaelic football. These different variations of football are known as football codes.

Various forms of football can be identified in history, often as popular peasant games. Contemporary codes of football can be traced back to the codification of these games at English public schools during the nineteenth century. The expanse of the British Empire allowed these rules of football to spread to areas of British influence outside of the directly controlled Empire, though by the end of the nineteenth century, distinct regional codes were already developing: Gaelic football, for example, deliberately incorporated the rules of local traditional football games in order to maintain their heritage. In 1888, The Football League was founded in England, becoming the first of many professional football competitions. During the twentieth century, several of the various kinds of football grew to become some of the most popular team sports in the world.

Football (video game)

Football (released as NFL Football) is a multiplayer sports video game produced by Mattel and released for its Intellivision video game system in 1979. The players each control a football team competing in a standard four-quarter game. Like Mattel's other sports video games, NFL Football did not use any official National Football League team names or player names, even though Mattel obtained a license from the NFL and used the league's logo in its box art.

Gameplay

The player controls a five-man football team, actively controlling one team member at a time, with the computer controlling the rest. As in traditional American football, the player's team must score more points than the opponent's team within the time limit of the game. The game consists of four quarters, each a simulated 15 minutes in length, and takes place on a horizontally scrolling 100-yard simulated football field.

Player 1 always starts the game on offense and receives the opening kick-off from Player 2; at the start of the second half, Player 2 will receive the kick-off from Player 1. NFL Football is played in the same basic manner as a regulation game of football, with the offense being given four downs to advance the ball a minimum of ten yards before losing possession of the football to the opposing team. At the start of each down, the players use their controller's keypad to input a formation and a play for that down; descriptions and diagrams of the plays were printed in the game's instruction manual and not visible on-screen. When both players have entered their formations, play resumes.

American football

American football (referred to as football in the United States and Canada, also known as gridiron elsewhere) is a sport played by two teams of eleven players on a rectangular field with goalposts at each end. The offense, the team with control of the oval-shaped football, attempts to advance down the field by running with or passing the ball, while the team without control of the ball, the defense, aims to stop their advance and take control of the ball for themselves. The offense must advance at least ten yards in four downs, or plays, or else they turn over the football to the opposing team; if they succeed, they are given a new set of four downs. Points are primarily scored by advancing the ball into the opposing team's end zone for a touchdown or kicking the ball through the opponent's goalposts for a field goal. The team with the most points at the end of a game wins.

American football evolved in the United States, originating from the sports of association football and rugby football. The first game of American football was played on November 6, 1869, between two college teams, Rutgers and Princeton, under rules based on the association football rules of the time. During the latter half of the 1870s, colleges playing association football switched to the Rugby Union code, which allowed carrying the ball. A set of rule changes drawn up from 1880 onward by Walter Camp, the "Father of American Football," established the snap, eleven-player teams, and the concept of downs; later rule changes legalized the forward pass, created the neutral zone, and specified the size and shape of the football.

Association (object-oriented programming)

In object-oriented programming, association defines a relationship between classes of objects that allows one object instance to cause another to perform an action on its behalf. This relationship is structural, because it specifies that objects of one kind are connected to objects of another and does not represent behaviour.

In generic terms, the causation is usually called "sending a message", "invoking a method" or "calling a member function" to the controlled object. Concrete implementation usually requires the requesting object to invoke a method or member function using a reference or pointer to the memory location of the controlled object.

The objects that are related via the association are considered to act in a role with respect to the association, if object's current state in the active situation allows the other associated objects to use the object in the manner specified by the role. A role can be used to distinguish two objects of the same class when describing its use in the context of the association. A role describes the public aspects of an object with respect to an association.