This C program serves as a basic example for a novice C programmer to understand function usage and structure. This C source code defines a set of functions that perform various mathematical operations. These operations include calculating the square of a number, reading an integer from the user, and computing the area of a rectangle. The main function of the program calls these functions with specific values and prints the results.

We have written this code to adhere to modern C coding standards such as proper function declarations, indentation, and the inclusion of the necessary header file for input/output operations.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 | #include <stdio.h> /* Examples of declarations of functions */ void square1(void); // Example of a function without input parameters and without return value void square2(int i); // Example of a function with one input parameter and without return value int square3(void); // Example of a function without input parameters and with integer return value int square4(int i); // Example of a function with one input parameter and with integer return value int area(int b, int h); // Example of a function with two input parameters and with integer return value /* Main program: Using the various functions */ int main(void) { square1(); // Calling the square1 function square2(7); // Calling the square2 function using 7 as actual parameter corresponding to the formal parameter i printf("The value of square3() is %d\n", square3()); // Using the square3 function printf("The value of square4(5) is %d\n", square4(5)); // Using the square4 function with 5 as actual parameter corresponding to i printf("The value of area(3,7) is %d\n", area(3, 7)); // Using the area function with 3, 7 as actual parameters corresponding to b, h respectively return 0; } /* Definitions of the functions */ /* Function that reads from standard input an integer and prints it out together with its sum */ void square1(void) { int x; printf("Please enter an integer > "); scanf("%d", &x); printf("The square of %d is %d\n", x, x * x); } /* Function that prints i together with its sum */ void square2(int i) { printf("The square of %d is %d\n", i, i * i); } /* Function that reads from standard input an integer and returns its square */ int square3(void) { int x; printf("Please enter an integer > "); scanf("%d", &x); return (x * x); } /* Function that returns the square of i */ int square4(int i) { return (i * i); } /* Function that returns the area of the rectangle with base b and height h */ int area(int b, int h) { return (b * h); } |

Output of the C Program:

Please enter an integer > 3

The square of 3 is 9

The square of 7 is 49

Please enter an integer > 4

The value of square3() is 16

The value of square4(5) is 25

The value of area(3,7) is 21