warning control reaches end of non-void function -Wreturn-type

Question

I am having a slight is regarding functions  I believe it is likely because I am not using them  My code is as follows     date difference calculator     include  lt stdio h gt   int main       int Date1   0  Date2   0  Dif  F  L  D1  D2  M1  M2  Y1  Y2    int x 13     0  31  28  31  30  31  30  31  31  30  31  30  31     int y 13     0  31  28  31  30  31  30  31  31  30  31  30  31     char A1  A2  B1  B2     input first date     fprintf  stderr    Enter first date in the form  lt day gt   lt month gt   lt year gt   or  lt day gt - lt month gt - lt year gt   nWhere  lt day gt   lt month gt  and  lt year gt  are integers  n      scanf   i c i c i    amp D1   amp A1   amp M1   amp B1   amp Y1       check first date     if    Y1   4   x 2  29   while   Y1  lt  1     Y1  gt  9999       M1  lt  1    M1  gt  12      D1  lt  1    D1  gt  x M1       A1    B1       A1          amp  amp   A1     -                    fprintf  stderr   Incorrect format  re-enter date  n           scanf   i c i c i    amp D1   amp A1   amp M1   amp B1   amp Y1          if    Y1   4   x 2  29            print first date     fprintf  stderr   First date    i c i c i n   D1   A1   M1   B1   Y1      input second date     fprintf  stderr    Enter second date in the form  lt day gt   lt month gt   lt year gt  or  lt day gt - lt month gt - lt year gt   nWhere  lt day gt   lt month gt  and  lt year gt  are integers  n      scanf   i c i c i    amp D2   amp A2   amp M2   amp B2   amp Y2       check second date     if    Y2   4   y 2  29   while   Y2  lt  1     Y2  gt  9999       M2  lt  1    M2  gt  12      D2  lt  1    D2  gt  y M2       A2    B2       A2          amp  amp   A2     -                    fprintf  stderr   Incorrect format  re-enter date  n           scanf   i c i c i    amp D2   amp A2   amp M2   amp B2   amp Y2          if    Y2   4   y 2  29            print second date     fprintf  stderr   Second date    i c i c i n   D2   A2   M2   B2   Y2      convert first date into days     for  F   1  Y1  gt  F   F                if  F   4    0   Date1   Date1   366        else  Date1   Date1   365          for  L   1  M1  gt  L   L          Date1   Date1   x L    Date1   Date1   D1     convert second date into days     for  F   1  Y2  gt  F   F                if  F   4    0   Date2   Date2   366        else  Date2   Date2   365          for  L   1  M2  gt  L   L          Date2   Date2   y L    Date2   Date2   D2     standard output     Dif   Date2 - Date1   printf   n i n n    Dif      text output     if  Date2  gt  Date1         Dif   Date2 - Date1      fprintf  stderr    Indicating that the first date is  i days before second date  n    Dif     if  Date1  gt  Date2         Dif   Date1 - Date2      fprintf  stderr    Indicating that the second date is  i days before first date  n    Dif      if  Date1    Date2        fprintf  stderr    Indicating that the first date is equal to second date  n         When compiling using this  gcc -Wall -ansi date1 c -o date1 This occurs   date1 c  In function    main     date1 c 70 1  warning  control reaches end of non-void function  -Wreturn-type    Is there a simple fix for this or do I have to write my program to use functions propely  I am unable to change how I compile the code as it has to follow a set spec   Apologies for the poor formatting of my question but this is my first time here and I was hoping to be able to do it alone   Hope someone can help

User · Accepted Answer

You just need to return from the main function at some point  The error message says that the function is defined to return a value but you are not returning anything                  if  Date1    Date2         fprintf  stderr    Indicating that the first date is equal to second date  n        return 0

User · Answer

You can also use EXIT SUCCESS instead of return 0   The macro EXIT SUCCESS is actually defined as zero  but makes your program more readable

[c++] warning: control reaches end of non-void function [-Wreturn-type]

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