Added 2 problems to Operator & Expression Chapter

book.toml

@@ -11,3 +11,4 @@ mathjax-support = true
 [output.html.code.hidelines]
 python = "~"
 c = "~"
+hint = "~"

src/Operator_and_Expression/Operator_and_Expression.md

@@ -1 +1,97 @@
 # Operator & Expression
+
+
+## Problems
+* ***Click on the title of the problem to submit your solution before looking at our solution.***
+* ***We discourage looking at our solution before attempting to solve it by yourself first.***
+
+1. **[Simple Calculator](https://vjudge.net/problem/Gym-287306C)**
+
+    Given two numbers X and Y. Print the summation and multiplication and subtraction of these 2 numbers.
+
+    ***Input***
+
+    Only one line containing two separated numbers \\(X, Y (1  ≤  X, Y  ≤  10 ^ 5)\\)
+
+    ***Output***
+
+    Print 3 lines that contain the following in the same order:
+
+    1. "\\(X + Y =\\) **summation result**" without quotes.
+    2. "\\(X * Y =\\) **multiplication result**" without quotes.
+    3. "\\(X - Y =\\) **subtraction result**" without quotes.
+
+    ***Examples***
+
+    Input
+    ```
+    5 10
+    ```
+
+    Output
+    ```
+    5 + 10 = 15
+    5 * 10 = 50
+    5 - 10 = -5
+    ```
+
+    ***Notes***
+
+    **Be careful with spaces.**
+
+    Hint:
+    ```hint
+    Press the eye icon to reveal hint.
+    ~ Use long long int instead of int
+    ~ Don't forget to use the designated format specifier for long long int (%lld)
+    ```
+
+    **Solution**
+
+    ```c
+    // Press the eye icon to reveal solution.
+    ~#include <stdio.h>
+ 
+    ~int main()
+    ~{
+    ~    long long x, y;
+    ~
+    ~    scanf("%lld %lld", &x, &y);
+    ~
+    ~    printf("%lld + %lld = %lld\n", x, y, x + y);
+    ~    printf("%lld * %lld = %lld\n", x, y, x * y);
+    ~    printf("%lld - %lld = %lld\n", x, y, x - y);
+    ~
+    ~    return 0;
+    ~}
+    ```
+
+2. **[Difference](https://vjudge.net/problem/Gym-287306D)**
+    
+    Hint:
+
+    ```hint
+    Press the eye icon to reveal hint.
+    ~ Use long long int instead of int
+    ~ Don't forget to use the designated format specifier for long long int (%lld)
+    ```
+
+    **Solution**
+
+    ```c
+    // Press the eye icon to reveal solution.
+    ~#include <stdio.h>
+
+    ~int main()
+    ~{
+    ~    long long a, b, c, d, x;
+    ~
+    ~    scanf("%lld %lld %lld %lld", &a, &b, &c, &d);
+    ~
+    ~    x = (a * b) - (c * d);
+    ~
+    ~    printf("Difference = %lld\n", x);
+    ~
+    ~    return 0;
+    ~}
+    ```

src/Recursion/Practice_on_Recursion.md

@@ -1,6 +1,6 @@
 # PRACTICE Recursion
 
-Some of the sollowing problems are directly copied from [Zobayer Hasan vai's blog post on recursion](https://zobayer.blogspot.com/2009/12/cse-102-practice-recursions.html). We are grateful to his open contributions towards learning CS.\
+Some of the following problems are directly copied from [Zobayer Hasan vai's blog post on recursion](https://zobayer.blogspot.com/2009/12/cse-102-practice-recursions.html). We are grateful to his open contributions towards learning CS.\
 You can use the [Competitive Programming Helper (cph)](https://marketplace.visualstudio.com/items?itemName=DivyanshuAgrawal.competitive-programming-helper) extension in VS code to make your practice easier though it wont make a big difference.
 
 <i>ALL THE BEST FOR YOUR HARD WORK.</i>