kinema game initial rust implementation

Author: P Marques

52_Kinema/rust/Cargo.toml

@@ -0,0 +1,7 @@
+[package]
+name = "rust"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+rand = "0.9.0"

52_Kinema/rust/src/main.rs

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+use std::io::Write;
+use rand::Rng;
+
+/** KINEMA BY RICHARD PAV
+ * https://github.com/coding-horror/basic-computer-games/blob/main/52_Kinema/kinema.bas
+ * Direct conversion from BASIC to Rust by Pablo Marques (marquesrs).
+ * As a faithful translation, many of the code here are done in an unrecommended way by
+ *  today's standards.
+ * 
+ * ATTENTION: The original code has mathematical imprecision and uses simplifications
+ * instead of the real formulation, which could lead to incorrect results. I have solved
+ * this issue, but kept the old lines. To compile the original version, just uncomment the 
+ * code with the OLD label and comment the lines with the NEW label.
+ * example: gravity is now 9.81 instead of 10
+ * 17/02/25
+*/
+
+fn subroutine(a: f64, q: &mut i32) {
+    std::io::stdout().flush().unwrap();
+    //500 INPUT G
+    let mut input = String::new();
+    let g;
+    loop {
+        std::io::stdin().read_line(&mut input).unwrap();
+        match input.trim().parse::<f64>() {
+            Ok(e) => { g = e; break; },
+            Err(_) => { print!("\nINVALID. TRY AGAIN: "); continue; },
+        };
+    }
+    //502 IF ABS((G-A)/A)<.15 THEN 510
+    if f64::abs((g-a)/a) < 0.15 {
+        //510 PRINT "CLOSE ENOUGH."        
+        print!("CLOSE ENOUGH.");
+        //511 Q=Q+1
+        *q = *q + 1;
+    }
+    else {
+        //504 PRINT "NOT EVEN CLOSE...."
+        print!("NOT EVEN CLOSE...");
+        //506 GOTO 512
+    }
+    //512 PRINT "CORRECT ANSWER IS ";A
+    print!("\nCORRECT ANSWER IS {a:.2}\n");
+    //520 PRINT
+    //530 RETURN
+}
+
+fn main() {
+    let mut rng = rand::rng();
+
+    //10 PRINT TAB(33);"KINEMA"
+    //20 PRINT TAB(15);"CREATIVE COMPUTING  MORRISTOWN, NEW JERSEY"
+    //30 PRINT: PRINT: PRINT
+    //100 PRINT
+    //105 PRINT
+    print!("{}KINEMA\n{}CREATIVE COMPUTING  MORRISTOWN, NEW JERSEY\n\n\n\n", 
+        " ".repeat(33),
+        " ".repeat(15)
+    );
+    loop {
+        //106 Q=0
+        let mut q = 0;
+        //110 V=5+INT(35*RND(1))
+        let v: f64 = 5.0 + 35.0 * rng.random_range(0.0..1.0);
+        //111 PRINT "A BALL IS THROWN UPWARDS AT";V;"METERS PER SECOND."
+        //112 PRINT
+        print!("\nA BALL IS THROWN UPWARDS AT {v:.2} METERS PER SECOND.\n");
+        //115 A=.05*V^2
+        //let a = 0.05 * v.powf(2.0); // OLD
+        let mut a = v.powf(2.0) / (2.0 * 9.81); // NEW
+        //116 PRINT "HOW HIGH WILL IT GO (IN METERS)";
+        print!("\nHOW HIGH WILL IT GO (IN METERS)? ");
+        
+        //117 GOSUB 500
+        subroutine(a, &mut q);
+        
+        //120 A=V/5
+        //a = v / 5.0; // OLD
+        a = 2.0 * v / 9.81; // NEW
+        //122 PRINT "HOW LONG UNTIL IT RETURNS (IN SECONDS)";
+        print!("\nHOW LONG UNTIL IT RETURNS (IN SECONDS)? ");
+        //124 GOSUB 500
+        subroutine(a, &mut q);
+
+        //130 T=1+INT(2*V*RND(1))/10
+        let t = 1.0 + (2.0 * v * rng.random_range(0.0..1.0) / 10.0);
+        //132 A=V-10*T
+        a = v + (-9.81 * t);
+        //134 PRINT "WHAT WILL ITS VELOCITY BE AFTER";T;"SECONDS";
+        print!("\nWHAT WILL ITS VELOCITY BE AFTER {t:.2} SECONDS? ");
+
+        //136 GOSUB 500
+        subroutine(a, &mut q);
+
+        //140 PRINT
+        //150 PRINT Q;"RIGHT OUT OF 3.";
+        print!("\n{q} RIGHT OUT OF 3.\n");
+        //160 IF Q<2 THEN 100
+        if q < 2 {
+            continue;
+        }
+        //170 PRINT "  NOT BAD."
+        //print!("  NOT BAD.");
+        //180 GOTO 100
+    }
+    //999 END
+}