C program not working with errors related to C++ -

i wrote program school, keep getting c++ related errors (apparently)

#include <stdio.h>     #define int num_of_chars 51      void switch (char *c)     {         //little letters         if (((*c)>=97) && ((*c)<=122))             (*c)-=32;         //capital letters         if ((c>=65) && (c<=90))             (*c)+=32;         //*c>=5         if ((c>=53) && (c<=57))             (*c)=56;         //*c<5         if ((c>=48) && (c<=52))             (*c)=48;     }*/      int main() {          char string[51];         printf("please enter string  \n");         scanf("%s", string);         printf("%s  =>  ", string);          int i=0;         char s[51];          while((string[i]!= "\0") && (i < num_of_chars))            {             s[i]=switch (string[i]);             i++;                }         printf("%s", s);         return 0;*/      } 

i'm getting errors /stray xxx in program , macro names must identified.

i'm kind of new c i'd appreciate if point me out errors in code are. thanks!!

there many issues. want program below. code compiles , works still absolutly horrible, respects intention.

try make better.

btw characters contained in string variable changed, intended ?

#include <stdio.h> #define num_of_chars 51    // removed "int"  char switchcase (char *c)  // << need return char not void {                          // << name changed switchcase   //  c changed (*c), btw: *c without () ok    //little letters   if (((*c) >= 97) && ((*c) <= 122))     (*c) -= 32;   //capital letters   else if (((*c) >= 65) && ((*c) <= 90))     (*c) += 32;   //*c>=5   else if (((*c) >= 53) && ((*c) <= 57))     (*c) = 56;   //*c<5   else if (((*c) >= 48) && ((*c) <= 52))     (*c) = 48;    return *c; }  int main() {    char string[51];   printf("please enter string  \n");   scanf("%s", string);   printf("%s  =>  ", string);    int = 0;   char s[51];    while ((string[i] != '\0') && (i < num_of_chars))   {     s[i] = switchcase(&string[i]);     i++;            //^ & missing here   }    s[i] = '\0';                   // << forgot 0 terminator   printf("%s", s);   return 0;                      // << removed stray "*/" }