Why didn't run the

CodePudding user response:

Need to input number three is the result

CodePudding user response:

The scanf said input, % lf said double-precision floating-point number

CodePudding user response:

No input number three

CodePudding user response:

The scanf waiting for your input, in addition, the output should use % lf rather than % f

CodePudding user response:

The scanf in waiting for you to input data, you need to be on the keyboard input number 1 (space) digital 2 (space) 3 (enter)

CodePudding user response:

Scandf is to let you input function, he called the number you entered to perform