Didn't bother compiling the entire thing, so I can't say for sure that it works, but it should get you on the right track.
#define STRINGSIZE 100
/* What are you doing? 'O' and 0 are not the same thing. */
void getString(char *string);
void reverseCase(char *string);
int numGraph(char *string);
printf("Entered string => %s\n",string);
count = numGraph(string);
printf("Number of graphic characters in string = %d\n", count);
printf("Reverse case => %s\n",string);
void reverseCase(char *string)
/* Reverse the case of all alphabetic characters in the string.
That is, all upper case characters become lower case and
all lower case become upper case.
int numGraph(char *string)
/* Calculate the number of printable graphic characters in the
for(i = 0,count = 0;string[i] != '\0';i++)
if (isgraph((int)string[i])) count++;
void getString(char *string)
printf("Please enter a string to process\n");
fgets(string, STRINGSIZE, stdin);