ok im having a little problem here

im trying to make a simple calculator in C, but everytime i run it and press enter for the first value, i get an error and it closes. here is the source code. please tell me if i messed up on something. Im very new to C and a little help would be great.

Code:#include<stdio.h> int main() { float operation; float x; float y; float answer; printf(" Type 1 for addition, 2 for multiplication, 3 for subtraction, or 4 for division\n"); printf(" Then type the two numbers.\n"); scanf("%s",operation); scanf("%f",x); scanf("%f",y); if(operation==1) { answer=x + y; } else if(operation==2) { answer=x * y; } else if(operation==3) { answer=x - y; } else { answer=x / y; } printf(" The answer is %f!\n",answer); getchar(); return 0; }