Sample Program with Multiple Functions

#include <stdio.h>

int computeSum(int num1, int num2);
int computeDifference(int num1, int num2);
int computeProduct(int num1, int num2);
float computeQuotient(int num1, int num2);

int main() {
	char op;
	int x, y;
	float z;

	scanf(" %c", &op);
	scanf("%d %d", &x, &y);

	switch (op) {
	case '+':
		printf("Sum = %d", computeSum(x, y));
		break;

	case '-':
		printf("Difference = %d", computeDifference(x, y));
		break;

	case '*':
		printf("Product = %d", computeProduct(x, y));
		break;

	case '/':
		z = computeQuotient(x, y);
		printf("Quotient = %.2f", z);
		break;

	default:
		printf("Invalid operator!");
		break;
	}
}

int computeSum(int num1, int num2) {
	return num1 + num2;
}

int computeDifference(int num1, int num2) {
	return num1 - num2;
}

int computeProduct(int num1, int num2) {
	return num1 * num2;
}

float computeQuotient(int num1, int num2) {
	return (float)num1 / (float)num2;
}