exponent modulus logarithm potential calling

src/main/c/Calculator/calculator.c

@@ -184,16 +184,32 @@ void displayMenu() {
     printf("19. Combination\n");
     printf("20. Exit\n");
 }
-int add(int num1, int num2) {
+double add(double num1, double num2) {
     return num1 + num2;
 }
 
-int subtract(int num1, int num2) {
+double subtract(double num1, double num2) {
     return num1 - num2;
 }
-int multiply(int num1, int num2) {
+double multiply(double num1, double num2) {
     return num1 * num2;
 }
-int divide(int num1, int num2) {
+double divide(double num1, double num2) {
     return num1 / num2;
-}
+}
+
+double exponent(double base, double exponent) {
+    return pow(base, exponent);
+}
+
+double modulus(double num1, double num2) {
+    return fmod(num1, num2);
+}
+
+double logarithm(double num) {
+    return log(num);
+}
+
+double potential(double base, double exponent) {
+    return pow(base, exponent);
+}