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# Menu-Driven program using Switch-case in C

Prerequisite : Switch Case in C
Problem Statement: Write a menu-driven program using Switch case to calculate the following: 1. Area of circle 2. Area of square 3. Area of sphere Also use functions input() and output() to input and display respective values.

## C

 `// C program to illustrate` `// Menu-Driven program` `// using Switch-case`   `#include ` `int` `input();` `void` `output(``float``);` `int` `main()` `{` `    ``float` `result;` `    ``int` `choice, num;` `    ``printf``("Press 1 to calculate area of circle\n");` `    ``printf``("Press 2 to calculate area of square\n");` `    ``printf``("Press 3 to calculate area of sphere\n");` `    ``printf``("Enter your choice:\n");` `    ``choice = input();` `    `  `    ``switch` `(choice) {` `    ``case` `1: {` `        ``printf``("Enter radius:\n");` `        ``num = input();` `        ``result = 3.14 * num * num;` `        ``printf``("Area of sphere=");` `        ``output(result);` `        ``break``;` `    ``}` `    ``case` `2: {` `        ``printf``("Enter side of square:\n");` `        ``num = input();` `        ``result = num * num;` `        ``printf``("Area of square=");` `        ``output(result);` `        ``break``;` `    ``}` `    ``case` `3: {` `        ``printf``("Enter radius:\n");` `        ``num = input();` `        ``result = 4 * (3.14 * num * num);` `        ``printf``("Area of sphere=");` `        ``output(result);` `        ``break``;` `    ``}` `    ``default``:` `        ``printf``("wrong Input\n");` `    ``}` `    ``return` `0;` `}` `int` `input()` `{` `    ``int` `number;` `    ``scanf``("%d", &number);` `    ``return` `(number);` `}`   `void` `output(``float` `number)` `{` `    ``printf``("%f", number);` `}`

Output:

```Press 1 to calculate area of circle
Press 2 to calculate area of square
Press 3 to calculate area of sphere
1