Question

I have this program in C that takes three char arrays that each have a first and last name. I have two functions that reverese the name and change it to all upper case. I have the program completeed but need to change both functions to use pointers instead of arrays. I will bold the functions I need to use pointers.

#include <stdio.h>

void upper_string(char []);

int main()
{
char name1[100]="John Smith";
char name2[100]="Mary Cohen";
char name3[100]="Carl Williams";
upper_string(name1);// calling upper case function
upper_string(name2);
upper_string(name3);
printf("Names are in upper case \n\"%s\"\n""%s\"\n""%s\"\n", name1,name2,name3);
reverse(name1);// calling reverse string function
reverse(name2);
reverse(name3);
  
getch();
}

void upper_string(char s[]) {
int c = 0;

while (s[c] != '\0') {
if (s[c] >= 'a' && s[c] <= 'z') {
s[c] = s[c] - 32;
}
c++;
}
}
// function to reverse the string
void reverse(char string[]){

char temp;
int i, j = 0;
i = 0;
j = strlen(string) - 1;

while (i < j) {
temp = string[i];
string[i] = string[j];
string[j] = temp;
i++;
j--;
}

printf("\nReverse string is :%s", string);
}

Answer 1

Hi,

I have modified the code and highlighted the code changes below.

#include <stdio.h>
#include <string.h>
void upper_string(char *);
void reverse(char *string);
int main()
{
char name1[100]="John Smith";
char name2[100]="Mary Cohen";
char name3[100]="Carl Williams";
upper_string(name1);// calling upper case function
upper_string(name2);
upper_string(name3);
printf("Names are in upper case \n\"%s\"\n""%s\"\n""%s\"\n", name1,name2,name3);
reverse(name1);// calling reverse string function
reverse(name2);
reverse(name3);
  
}
void upper_string(char *s) {
int c = 0;
while (*(s + c) != '\0') {
if (*(s + c) >= 'a' && *(s + c) <= 'z') {
*(s + c) = *(s + c) - 32;
}
c++;
}
}
// function to reverse the string
void reverse(char *string){
char temp;
int i, j = 0;
i = 0;
j = strlen(string) - 1;
while (i < j) {
temp = *(string + i);
*(string + i) = *(string + j);
*(string + j) = temp;
i++;
j--;
}
printf("Reverse string is :%s\n", string);
}

Output:

sh-4.2$ gcc -o main *.c                                                                                                                                                                                                                                

sh-4.2$ main                                                                                                                                                                                                                                           

Names are in upper case                                                                                                                                                                                                                                

"JOHN SMITH"                                                                                                                                                                                                                                           

MARY COHEN"                                                                                                                                                                                                                                            

CARL WILLIAMS"                                                                                                                                                                                                                                         

Reverse string is :HTIMS NHOJ                                                                                                                                                                                                                          

Reverse string is :NEHOC YRAM                                                                                                                                                                                                                          

Reverse string is :SMAILLIW LRAC