What am I doing wrong with this C program? - c

Question

I have the following code, and the only thing I can physically see it evaluating is line 18 which is the call to printf(). It doesn't go any further.
#include <stdio.h>
#include <stdlib.h>
int main (void) {
int cylNum;
double disp, pi, stroke, radius;
pi = 3.14159;
printf("Welcome to the Engine Displacement Calculator!\n");
cylNum = scanf("Enter number of cylinders (then press enter): \n");
stroke = scanf("Enter stroke: \n");
radius = scanf("Enter radius: \n");
disp = radius * radius * pi * stroke * cylNum;
printf("Displacement is: %f", disp);
getchar();
printf("Press any key to exit!");
return 0;
}

Answer 1

the variables you're trying to read should be parameters to "scanf()", not the result of scanf():
printf("Enter number of cylinders (then press enter): ");
scanf("%d", &cylNum);
...

Answer 2

The scanf function is to read in values.
So the line
cylNum = scanf("Enter number of cylinders (then press enter): \n");
should be the following lines
printf("Enter number of cylinders (then press enter): \n");
scanf("%d", &cylNum);
You need to check the return value of scanf to make sure that it is 1, i.e. conversion has taken place.
So perhaps the code should read
do {
printf("Enter number of cylinders (then press enter): \n");
} while (scanf("%d", &cylNum) != 1);
For the variables disp, pi, stroke, radius you need to use "%lf" in the scanf function instead of "%d.
See scanf and printf

Answer 3

"scanf" doesn't take parameter like the way you are trying.
printf("Enter number of cylinders (then press enter): \n");
scanf(" %d", &cylNum);
printf("Enter stroke: \n");
scanf(" %lf", &stroke);

Answer 4

#include <stdio.h>
#include <stdlib.h>
int main (void) {
int cylNum;
float disp, pi, stroke, radius;
pi = 3.14159;
printf("Welcome to the Engine Displacement Calculator!\n\n");
printf("Enter number of cylinders (then press enter): ");
scanf("%d", &cylNum);
printf("Enter stroke: ");
scanf("%f", &stroke);
printf("Enter radius: ");
scanf("%f", &radius);
disp = radius * radius * pi * stroke * cylNum;
printf("Displacement is: %f\n\n", disp);
return 0;
}