Interest Calculator In C++

#include<iostream>
#include<cmath>
#include<string>

using namespace std;

float simple_interest(float a, float b, int c){
    float si = (a*b*c)/100;
    return si;
}

float compound_interest(float x, float y, int z){
    float ci = x*pow((1+y/100),z)-x;
    return ci;
}

int main(){
    float p, r;
    int t;
    string m;
    cout<<"Enter your Principal Amount: ";
    cin>>p;
    cout<<"Enter your Rate of Interest: ";
    cin>>r;
    cout<<"Enter your Time: ";
    cin>>t;
    cout<<"****************"<<endl;
    cout<<"Type of Interest(s for SI and c for CI): ";
    cin>>m;
    if(m=="c"){
        cout<<"Compound Interest is: "<<compound_interest(p,r,t);
    }
    else if(m=="s"){
        cout<<"Simple Interest is: "<<simple_interest(p,r,t);
    }
    else{
        cout<<"Please select between SI & CI";
    };

    return 0;
}