"Hello, World!" hello.c #include <stdio.h> int main(void) { printf("Hello, World!"); } Let's describe the program source code: we first import the stdio library (the name stands for standard available for others to use. Some other libraries are 6 built into the compiler. Like stdio and others. stdio is the libraries that provides the printf() function. This function is wrapped into specify the type of the argument. That's because this is a function invocation. Somewhere, inside the stdio library, printf is defined as int printf(const char *format, ...); You don't need to understand

e n u s i n g t h e Effects l i b r ar y : module Main import Effects import Effect.StdIO hello : Eff () [STDIO] hello = putStrLn “Hello world!” main : IO () main = run hello As u s u al , t h e e Al l main h as t o d o i s i n v ok e t h e hello f u n c t i on w h i c h s u p p or t s t h e STDIO e ff e c t f or c on s ol e I /O , an d r e t u r n s t h e u n i t v al u e . Al l p r ogr am s u r y ( p age 95) . 3. 3. 1 C on s ol e I /O C on s ol e I /O i s s u p p or t e d w i t h t h e STDIO e ff e c t , w h i c h al l ow s r e ad i n g an d w r i t i n g c h ar ac t e r s an d s t r i n

奥 奮 奵 女 奩 奮 奧 奴 奨 奥 Effects 奬 奩 奢 奲 奡奲 她 夺 module Main import Effects import Effect.StdIO hello : Eff () [STDIO] hello = putStrLn "Hello world!" main : IO () main = run hello 奁女 奵 女 奵 奡奬 夬 奴 奨 奥 奥 main央 奁奬 奬 main 奨 奡女 奴 奯 奤 奯 奩 女 奩 奮 奶 奯奫 奥 奴 奨 奥 hello 奦 奵 奮 奣 奴 奩 奯奮 奷 奨 奩 奣 奨 女 奵 奰 奰 奯奲 奴 女 奴 奨 奥 STDIO 奥 夛 奥 奣 奴 奦 奯奲 奣 奯奮 女 奯奬 奥 奉 夯奏 夬 奡奮 奤 奲 奥 奴 奵 奲 奮 女 奴 奨 奥 奵 奮 奩 奴 奶 奡奬 奵 奥 央 奁奬 奬 奰 奲 奯奧奲 奡奭 女 奵 r y 夨 姩 妡妵 失夳夳天 央 4. 3. 1 C on s ol e I /O 奃 奯奮 女 奯奬 奥 奉 夯奏 奩 女 女 奵 奰 奰 奯奲 奴 奥 奤 奷 奩 奴 奨 奴 奨 奥 STDIO 奥 夛 奥 奣 奴 夬 奷 奨 奩 奣 奨 奡奬 奬 奯奷 女 奲 奥 奡奤 奩 奮 奧 奡奮 奤 奷 奲 奩 奴 奩 奮 奧 奣 奨 奡奲 奡奣 奴 奥 奲 女 奡奮 奤 女 奴 奲 奩 奮 奧女

e n u s i n g t h e Effects l i b r ar y : module Main import Effects import Effect.StdIO hello : Eff () [STDIO] hello = putStrLn "Hello world!" main : IO () main = run hello As u s u al , t h e e Al l main h as t o d o i s i n v ok e t h e hello f u n c t i on w h i c h s u p p or t s t h e STDIO e ff e c t f or c on s ol e I /O , an d r e t u r n s t h e u n i t v al u e . Al l p r ogr am s u u m m a r y ( p age 132) . C on s ol e I /O C on s ol e I /O i s s u p p or t e d w i t h t h e STDIO e ff e c t , w h i c h al l ow s r e ad i n g an d w r i t i n g c h ar ac t e r s an d s t r i n

e n u s i n g t h e Effects l i b r ar y : module Main import Effects import Effect.StdIO hello : Eff () [STDIO] hello = putStrLn "Hello world!" main : IO () main = run hello As u s u al , t h e e Al l main h as t o d o i s i n v ok e t h e hello f u n c t i on w h i c h s u p p or t s t h e STDIO e ff e c t f or c on s ol e I /O , an d r e t u r n s t h e u n i t v al u e . Al l p r ogr am s u u m m a r y ( p age 132) . C on s ol e I /O C on s ol e I /O i s s u p p or t e d w i t h t h e STDIO e ff e c t , w h i c h al l ow s r e ad i n g an d w r i t i n g c h ar ac t e r s an d s t r i n

e n u s i n g t h e Effects l i b r ar y : module Main import Effects import Effect.StdIO hello : Eff () [STDIO] hello = putStrLn “Hello world!” main : IO () main = run hello As u s u al , t h e e Al l main h as t o d o i s i n v ok e t h e hello f u n c t i on w h i c h s u p p or t s t h e STDIO e ff e c t f or c on s ol e I /O , an d r e t u r n s t h e u n i t v al u e . Al l p r ogr am s u u m m a r y ( p age 133) . C on s ol e I /O C on s ol e I /O i s s u p p or t e d w i t h t h e STDIO e ff e c t , w h i c h al l ow s r e ad i n g an d w r i t i n g c h ar ac t e r s an d s t r i n

e n u s i n g t h e Effects l i b r ar y : module Main import Effects import Effect.StdIO hello : Eff () [STDIO] hello = putStrLn "Hello world!" main : IO () main = run hello As u s u al , t h e e Al l main h as t o d o i s i n v ok e t h e hello f u n c t i on w h i c h s u p p or t s t h e STDIO e ff e c t f or c on s ol e I /O , an d r e t u r n s t h e u n i t v al u e . Al l p r ogr am s u u m m a r y ( p age 132) . C on s ol e I /O C on s ol e I /O i s s u p p or t e d w i t h t h e STDIO e ff e c t , w h i c h al l ow s r e ad i n g an d w r i t i n g c h ar ac t e r s an d s t r i n

e n u s i n g t h e Effects l i b r ar y : module Main import Effects import Effect.StdIO hello : Eff () [STDIO] hello = putStrLn "Hello world!" main : IO () main = run hello As u s u al , t h e e Al l main h as t o d o i s i n v ok e t h e hello f u n c t i on w h i c h s u p p or t s t h e STDIO e ff e c t f or c on s ol e I /O , an d r e t u r n s t h e u n i t v al u e . Al l p r ogr am s u r y ( p age 139) . 4. 3. 1 C on s ol e I /O C on s ol e I /O i s s u p p or t e d w i t h t h e STDIO e ff e c t , w h i c h al l ow s r e ad i n g an d w r i t i n g c h ar ac t e r s an d s t r i n

e n u s i n g t h e Effects l i b r ar y : module Main import Effects import Effect.StdIO hello : Eff () [STDIO] hello = putStrLn “Hello world!” main : IO () main = run hello As u s u al , t h e e Al l main h as t o d o i s i n v ok e t h e hello f u n c t i on w h i c h s u p p or t s t h e STDIO e ff e c t f or c on s ol e I /O , an d r e t u r n s t h e u n i t v al u e . Al l p r ogr am s u u m m a r y ( p age 132) . C on s ol e I /O C on s ol e I /O i s s u p p or t e d w i t h t h e STDIO e ff e c t , w h i c h al l ow s r e ad i n g an d w r i t i n g c h ar ac t e r s an d s t r i n

e n u s i n g t h e Effects l i b r ar y : module Main import Effects import Effect.StdIO hello : Eff () [STDIO] hello = putStrLn "Hello world!" main : IO () main = run hello As u s u al , t h e e Al l main h as t o d o i s i n v ok e t h e hello f u n c t i on w h i c h s u p p or t s t h e STDIO e ff e c t f or c on s ol e I /O , an d r e t u r n s t h e u n i t v al u e . Al l p r ogr am s u r y ( p age 138) . 4. 3. 1 C on s ol e I /O C on s ol e I /O i s s u p p or t e d w i t h t h e STDIO e ff e c t , w h i c h al l ow s r e ad i n g an d w r i t i n g c h ar ac t e r s an d s t r i n