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问题:
I try to read-in 2 values using scanf() in C, but the values the system writes into memory are not equal to my entered values. Here is the code:
double a,b; printf("--------\n"); //seperate lines scanf("%ld",&a); printf("--------\n"); scanf("%ld",&b); printf("%d %d",a,b);
If I enter 1 and 2, CMD returns a correct, but b = -858993460 Here is what I already tried: using float or int instead of double, using scanf_s, using scanf("%d or %f for %i or %li or %lf or %e or %g ), using fflush(stdin) to clear keyboard buffer, reading in b first, trying like all possible combinations. I found out that there is a problem with the length of double on 32 bit OS, so that you are forced to use scanf("%lf", &f) to read in a double. No matter what I do, second value is always wrong.
I use MS VS express 2012 for Desktop on Windows 7 32 bit OS.
回答1:
Use the %lf format specifier to read a double:
double a; scanf("%lf",&a);
Wikipedia has a decent reference for available format specifiers.
You'll need to use the %lf format specifier to print out the results as well:
printf("%lf %lf",a,b);
回答2:
As far as i know %d means decadic which is number without decimal point. if you want to load double value, use %lf conversion (long float). for printf your values are wrong for same reason, %d is used only for integer (and possibly chars if you know what you are doing) numbers.
Example:
double a,b; printf("--------\n"); //seperate lines scanf("%lf",&a); printf("--------\n"); scanf("%lf",&b); printf("%lf %lf",a,b);
回答3:
You are using wrong formatting sequence for double, you should use %lf instead of %ld:
double a; scanf("%lf",&a);
回答4:
Format specifier in printf should be %f for doubl datatypes since float datatyles eventually convert to double datatypes inside printf.
There is no provision to print float data. Please find the discussion here : Correct format specifier for double in printf
回答5:
Using %lf will help you in solving this problem.
Use :
scanf("%lf",&doub)
