repo with tasks HowProgrammingWorks#4

Author: Elena Kononchuk

Exercises/1-for.js

@@ -1,9 +1,11 @@
-'use strict';
+"use strict";
 
 const sum = (...args) => {
-  // Use for loop and accumulator variable
-  // to calculate sum of all given arguments
-  // For example sum(1, 2, 3) should return 6
+  let res = 0;
+  for (let i = 0; i < args.length; i++) {
+    res += args[i];
+  }
+  return res;
 };
 
 module.exports = { sum };

Exercises/2-for-of.js

@@ -1,9 +1,11 @@
-'use strict';
+"use strict";
 
 const sum = (...args) => {
-  // Use for..of loop and accumulator variable
-  // to calculate sum of all given arguments
-  // For example sum(1, 2, 3) should return 6
+  let res = 0;
+  for (const num of args) {
+    res += num;
+  }
+  return res;
 };
 
 module.exports = { sum };

Exercises/3-while.js

@@ -1,9 +1,11 @@
-'use strict';
+"use strict";
 
 const sum = (...args) => {
-  // Use while loop and accumulator variable
-  // to calculate sum of all given arguments
-  // For example sum(1, 2, 3) should return 6
+  let res = 0;
+  while (args.length > 0) {
+    res += args.shift();
+  }
+  return res;
 };
 
 module.exports = { sum };

Exercises/4-do-while.js

@@ -1,9 +1,12 @@
-'use strict';
+"use strict";
 
 const sum = (...args) => {
-  // Use do..while loop and accumulator variable
-  // to calculate sum of all given arguments
-  // For example sum(1, 2, 3) should return 6
+  if (args.length === 0) return 0;
+  let res = 0;
+  do {
+    res += args.shift();
+  } while (args.length > 0);
+  return res;
 };
 
 module.exports = { sum };

Exercises/5-reduce.js

@@ -1,8 +1,5 @@
-'use strict';
+"use strict";
 
-const sum = (...args) => 0;
-// Use Array.prototype.reduce method
-// to calculate sum of all given arguments
-// For example sum(1, 2, 3) should return 6
+const sum = (...args) => args.reduce((acc, args) => acc + args, 0);
 
 module.exports = { sum };

Exercises/6-matrix.js

@@ -1,9 +1,15 @@
-'use strict';
+"use strict";
 
-const max = matrix => {
-  // Use nested for loop to find max value in 2d matrix
-  // For example max([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
-  // should return 9
+const max = (matrix) => {
+  let arr2d = matrix[0][0];
+  for (let i = 0; i < matrix.length; i++) {
+    const row = matrix[i];
+    for (let a = 0; a < row.length; a++) {
+      const col = row[a];
+      if (arr2d < col) arr2d = col;
+    }
+  }
+  return arr2d;
 };
 
 module.exports = { max };

Exercises/7-ages.js

@@ -1,19 +1,12 @@
-'use strict';
+"use strict";
 
-const ages = persons => {
-  // Use for..in to calculate age for each person
-  // For example ages({
-  //   lenin: { born: 1870, died: 1924 },
-  //   mao: { born: 1893, died: 1976 },
-  //   gandhi: { born: 1869, died: 1948 },
-  //   hirohito: { born: 1901, died: 1989 },
-  // })
-  // should return {
-  //   lenin: 54,
-  //   mao: 83,
-  //   gandhi: 79,
-  //   hirohito: 88,
-  // }
-};
+const ages = (persons) => {
+  const staf = {};
 
+  for (const i in persons) {
+    const info = persons[i];
+    staf[i] = info.died - info.born;
+  }
+  return staf;
+};
 module.exports = { ages };